Some more images!

If you could grab enough room up to the architrave/door frame you could go for a 760mm x 900mm quadrant shower enclosure, space saver sink 450/500mm wide with semi pedestal or vanity unit & space saver wc. If it would be possible a flat towel radiator on wall door opens on to, UFH as an alternative.

Hope this helps & good luck!

Regards Karl

Theres a storage heater outside the door im going to replace with a large towel radiator.
Im planning to replace the door with a bifold door into the bathroom too I think.

Wall to architrave is 73cm, if I take off the architrave its 78cm, that includes the thickness of existing tiles too :-(

Is there any possibility to move the entrance wall for 0,5m outside the bathroom?
If it is: you could get shower 70x90 cm with sliding door on one side, exchange WC and sink their places, getting a lot of space for shelfs above the WC.

Ive used a brilliant free design programme by ideal standard. Not sure if you did your own plan, but it's v v easy to add in your window and other room details then you can move things around (add their products to your room)

Just a few other ideas...

1) have you considered a 1500 bath with shower over (bi fold screen) going up to the window down that side?
You would then move the sink next to the WC so they are both facing you.
You can get compact versions or the unit mentioned in the above comment.

2) still move the sink right next to the WC and have an offset shower so it's longer and curved) could you get an 800 width next to the door??)

3) the quadrant shower is the only other option if you want to keep everything in the same place ie corner shower with curved front.

The main entrance door would be fine left as it is.

One thing I'm confused about is the door/cupboard leading into the bathroom?? With clothes hanging up? What's this please?

Without measuring and looking deep into
A wet room could remove the glass screens and move the sink next too the toilet
Or same as but a short fixed shower screen to protect the door area

@NK Interior Design - No chance to move the wall unfortunately. Although swapping the toilet and sink has been something I have considered. I have attached a very crude outline of the upstairs the bathroom furniture is not to scale as it was done ages ago as a rough outline but it gives you an idea of the space im working to.

@minnie101 the combined unit is a great idea I had not considered. I had looked at a square inset sink right up in the corner with the taps almost on the window sill to the side of the bowl. Maybe on a solid oak shelf, but the inset is a really good idea I may also be able to swop the sink and toilet around.

@Tani Harvey-Smith Im not bothered about keeping anything in the same place. I could look at getting thinner plasterboard and tiles for the wall buts only going to give me mm. I think the max width is 78cm to the door and that would mean no architrave which would look a bit odd.

The 1500 bath option I have considered, but it only leaves 700m for a toilet and sink which seems cramped.

The clothes are in the landing above a storage heater, I also have a dehumidifier above the stairs. I put washing out here before going to bed and its dry by the morning. It looks worse in the pic, but it doesnt stop you walking into the bathroom at night if you need too. I just took the pic without really tidying up. You can see it better here https://www.dropbox.com/s/lcvepvxrlpu4m9l/IMG_20141118_110151.jpg?dl=0 or attached pic.

Thanks for all the great tips so far I think I need to somehow visualise all this in some plans and see what works best. Im tempted to rip everything out back to the walls and replace with thinner plasterboard on the two internal walls to gain every 10mm of space possible.

@Smarter Properties - I was advised against a wet room as its upstairs and would require tanking and a lot of prep work to make sure it wouldnt leak. I was looking at those walk in shower trays as they are almost wet room like, but they seem to big :-( Plus I think the waste outlet is above the floor level (hence the boxing in) around the room.

Just another thought. We had the same size shower and doors in our last en suite. We didn't actually use the room for years until we refitted it (water pressure also being an issue). We just had a normal door fitted but went for one of the acqualisa digital showers. To us personally, having a really good shower is far preferable to being in a big space. Have been to many hotels with lovely walk in showers or wet rooms but the water has let it down! You do need to make sure the tray is deep enough though as they are powerful. I sound like I'm an advertisement for acqualisa! (I'm not, the plumber recommended!)

The shower is actually the best thing about that little room at the mo! But I will look into a new shower too.
The quadrant shower and compact unit seems like my favourite idea at the mo!

Instead of a bifold door have you thought of a sliding door? Something like this? http://houzz.com/photos/1877568

Have you thought about changing it to a wet room? That way you wouldn't need the screen? Would be more work but could be more useful longterm. My brother has a wet room as his ensuite and it works really well.

Go for a wet room! I have one in a small bathroom on the first floor and it's awesome. Yes, it requires tanking but it's totally worth it. Also a wall hung toilet and a wall hung sink will look much better.

I hate to state the obvious, but your bathroom would look much bigger if it was just a bathroom and not a store room. Most of what you have on display could be stored in a corner wall cupboard. De-clutter. You would be surprised at the difference. As a start take everything out that is not screwed to the floor, take a picture, and then look at this new bathroom look.

I'm sure I've seen on houzz loo and sink units that are combined. Alternatively, how about a wall hung loo and a sink with storage underneath. If you put them next to each other you could fit a larger shower unit. If not a wet room, how about a walk in shower. It would look bigger I think, and decent storage to put your stuff away in. Good luck!

Moving the WC to where the sink is ( and tucking closer to the window wall) coupled with corner sink to the right of the window would give you space for a larger shower tray whilst maintaining reasonable circulation.

Could you replace the back wall of the shower with a bespoke frosted glass panel? This would give extra space in the shower and also as an added benefit extra light on the landing.

If you add a wall mounted sink, it would give the look of more floor space which would instantly make the room feel bigger. A glass sink works well because you can see through it and again gives the illusion of space. Keep floor tiles and wall tiles the same another trick to make the room feel bigger!

Quadrant shower with sliding doors would be your best option. The lighting is very important keep everything light and bright.

Mirrors will double the size of the room too!

If you moved the bedroom door backwards you could put a sliding door on the shower room, (a bifold door wouldn't last as long as a slider) What about a corner toilet that curves inward down to the floor so it appears to be floating but is solidly placed. (Oh and get a dual flush to save water) I have seen a non-corner version of this recently in a very white bathroom I think in a London flat on the Houzz newsletter. Search "white bathroom" in Houzz photos, maybe. Anyway a corner loo would allow you to move the sink to under the window thus gaining a little space for a larger shower. Clutter/storage are issues which could be solved with a deep under sink drawer but have the unit floating so you can still see the floor. Your cork floor tiles are nice and on trend if you can keep them at all. Also a large mirror maybe attached to wall from halfway up or so, in a big seamless pane as you enter maybe, would visually double the space and light.

have you considered blocking off the window (possible velux instead?) then move everything around anticlockwise....shower directly in front of the door where the loo is now. WC where the basin was, and a vanity on the same wall as the door.

Thanks for all the comments, they are much appreciated. I am going to try and answer everyone! I think I have a plan outined at the bottom of the following comments/replies.

@clofty24 - yes a sliding door was considered but it would either take more room out of the bathroom or consist of major work outside the door.

@lottie27111975 @karrrla @tryphic - walk in shower/wet room would be ideal but would require quite a lot of work and as its upstairs been advised against it. Although im getting a second opinion from a local tiler soon.

@Ensign Accessories I just photographed at a bad time, most of the time its not so cluttered. However it is the only space to store a lot of the stuff, so hence the many storage options. Corner unit is a no go because the room has no available corners (shower, window, door, toilet).

@Rachel FitzGerald I think the toilet needs to stay where it is due to the plumbing of the large waste pipe and the fact my walls are 1.2m thick!

@baxterh the back wall doesnt go onto the landing its inside the other bedroom but replacing the wall is currently not an option. Nice idea though :-)

@Sharon Boughedda The matching tiles is a good idea, I was only going to tile the shower area and paint the rest a teal colour. But the floor could defo match. I think im going for a unit top sink, but place it partly on the windowsill (which is huge) and partly on a new unit. The window is huge so adds lot of light during the day.

@kittihawke I think moving the doors is unworkable unfortunately as that would make more room. i hate the floor tiles so might have to have another look at ripping them up!

@jonathandb1972 the window is an original sash window and it would be criminal to block it off I feel. Plus it gives the bathroom a lot of light which helps to alleviate the size issue a bit. Velux isnt possible due to loft above.

I think im going to put in 760x900 quadrant shower, with a frameless design so its less imposing.
The toilet will stay where it is but with a back wall toilet onto a hidden cistern. Two 500mm cabinets next to each other one with the toilet and another with the sink on top, and worktop on top of the cabinets which goes back and over the windowsill too. The sink will then be half on the cabinet and half on the windowsill (which is big). B+Q are the only place I have found which seem to do slimline cabinets which will make it all fit. Im trying to find a bit of planning software that includes B+Q items and also allows me to include the windowsill!! The tap to the sink will be to the side of the basin so all the plumbing can be in the under cabinet.

Essentially two units like in this image (but the other way around, and in Oak not white!), and with a solid oak worktop going back into the window as well as along the wall. I forgot to mention a towel radiator where the current sink is!

The above is a total of 1100mm wide.
http://www.diy.com/rooms/cooke-lewis-appleby-gloss-white-slimline-toilet-cabinet/406194_BQ.prd

@Paul McCann,
don't forget that you can leave the sash window on the outside even if you cover the inside - outwardly it looks unchanged. Just because there is a loft above doesn't exclude the possibility of a velux. Any builder could make a square tunnel from your bathroom ceiling to the velux and light sources above let more light in than wall windows. I understand the desire to keep it but it does seem very large for the room.

I think we have a solution. We were originally going to have a back to wall toilet up against a cabinet like the sink unit with a concealed cistern, but it turns out even a slimline cabinet and btw toilet takes up more room than a lot of toilets. So fitting a space saving toilet saved even more room.

Some things to note
1, the shower in the pic is 800x800 because thats the closest I could get in the planner. The actual size will 760x900. So it will be a bit further away from the door and slightly nearer the sink.

2, The unit is the same height as the windowsill so the sink will sit on both the unit and windowsill allowing for a nice large freestanding sink with tap to the side.

3, the colours are just for contrast.

I didn't have time to read all of the comments on here but wondered if you'd seen the Labette mini bath. We had one in Italy, with a shower over (not usually my favourite, but with it was an elegant solution with wall mounted taps, controls and showerhead. A plain panel of glass completed it. Bath dimension starts at 108 x 70