I don't think you have the room for an oblong shower. It leaves you with only a 60cm gap to put the vanity. The toilet looks weird if you don't put it in the middle of the window too. Although, if you do put it in the middle of the window, you may have room for a little more storage on the right hand wall as you walk in . The vanity in your plan would have to go right up to the glass of the shower, as the bath will unlikely to be no less than 700 wide. 700 plus 600 for the vanity and 800 for the shower is 2100mm ( your total ) I think you can improve on this layout. You can get baths with storage underneath. I'd change the shower for an offset quadrant at 800 x 1200mm. I'd move the Vanity and Toilet to the right hand wall and have a combination vanity / toilet. You can then fit extra storage in to the gap between the shower and the boiler without making it look cramped.

@keiblem I'm starting to think so too! @LTS yes it is @McKiernan Architects Ltd. Thank you! I believe there is a small basin in the room with the toilet (the image was taken from the estate agents website so they must have have drawn it in). But agreed with @Carolina we would need another sink in the bathroom, as you say we should be able to fit a small one! @minnie10 yes similar idea to above, I will try this out on paper, seems like the best option. Thank you everyone!

The crucial thing with moving a toilet - on a practical level - is understanding where the soil pipe is. If it's currently behind the existing loo, you'll have a lot of ugly boxing to hide the pipe if the loo is in the bay window. On an aesthetic level, I have to say I think it would look odd, and it would be very much the first thing you see when you open the door. Positioning something in a bay window conveys a sense of importance to it, so I think it will look like the toilet is your most treasured thing in the room :) I think in your shoes I would move the toilet 90 degrees so it's on the side wall, and install a single, beautiful sink unit in place of the existing one. The bathroom isn't huge so I think you need to question how often you would genuinely use a double sink - would you really ever have two people in there at once? Double sinks are lovely and we are all hankering after them because you see so many stylish pictures of them (I think they appeal to a human need for symmetry!) - but the greatest luxury you can have is a sense of space, and I think the room would feel cramped if you try to squeeze one in. Better to spend your budget on a single beautiful sink, create symmetry with wall lights around the mirror, and position a huge houseplant in the bay window (get rid of the bidet first, obviously!). You could consider moving the loo to where the sink currently is, changing the way the door opens to the other side - so the loo would effectively be hidden when you open the door. The boxing would sit more comfortably on that side. Not sure if there is room for the loo with enough space in front of it there though, so you'd need to check that out with accurate measurements.

My bathroom is slightly smaller, with a depth of about 170cm, and a width of 180/220. At the beginning it was the usual bathroom with a bath, basin, and WC, but we traded the bath for a shower, and we stole some space from the adjacent room to make space for a bidet (we're the stereotypical Italians ;)) it feels much more spacious than its size... Here's the result