Can you post a floor plan please? Helps to visualise the space.

It would also be useful for you to look at where the drains are in your garden. If the drain runs past the other end of your house, it might be really easy to plumb into.

Also - you might need to consider the direction of your floor joists. We have moved toilets in the past and have been able to run the soil pipe in the floor space. However when we recently did our current bathroom, we couldn’t move it to my preferred location because the direction of the joists didn’t allow it.

The first 2 show existing, the last one is what we are planning to do - shift the bathroom slightly forwards to take some of the front bedroom which will be a spare room, and extend the back bedroom over the top of the kitchen.

The drains are at the side of the house, ie the same side as the current bathroom. As for the floor joists, as we are extending the back bedroom and the current floor boards feel very wonky under the carpet, I think they will probably be ripped up anyway, although not sure if this is quite the same thing as the floor joists!
We don’t need a big ensuite, and not massively fussed if it has a window or not. I am rubbish at visualising so my husband keeps telling me I need to think of that bedroom space as a blank canvas and not be swayed by what is already there

When we redid the main bathroom about 12 years ago we did move the toilet position at the time. Also, not set on the layout of the bathroom as shown on the 3rd pic as will probably try to avoid having the toilet right in front of the door

Can I ask why you are adverse to the corridor feel as you go into the room? Looking at your plans - the room opens up at back where the extension is, and I’m guessing with those lovely large windows at the end, this is where you would like your sleeping area?? If it is, it makes sense to have your bathroom and wardrobe at the door end. Think about standard hotel rooms - that’s kind of what they do to ensure a larger squarer sleeping area. The width of the room as you go in is around 2.8m - this area would feel cramped with a bed - however would work really well with the en-suite!

Yep it’s my husband who has the thing about the ‘corridor’, he keeps saying it’s a waste of space but I don’t really see much of a way around it. Also, re the window at the back - the current window (which will go anyway when extended) is too large to be honest, it’s something like 210cm wide by 150cm high, and as we get the sun full pelt in the morning at the back, it’s pretty dazzling. So was thinking maybe if the ensuite was at the back in the corner then that would possibly give us more options somehow. As I said I’m rubbish at visualising!!