What do you want in the ensuite? Double vanity? Double shower? Bath? If so, what kind of bath? A separate / private toilet? I think the answers to those questions will direct you to what shape room will best meet your requirements. But, in general, a long, narrow design seems to be the most appropriate, with the shower at one end, sink/s in the middle and toilet at the other end.

Annb1997. Thanks for your suggestions. I don't think I need a heated towel rack if have a central heating radiator. A hanging rack would go above this perhaps too but also near the shower. In my lomg experience of CH the towels dry off fine in winter this way. In summer also when radiator not on if the window is open. I really do not like sliding doors on showers so have to find a solution with a 1000mm square shower with door. I have spent two hours today in a showroom looking at all possible combinations. Clearance is insufficient with certain size fixtures as you state with the vanity in the new position. So my homework tonight was choose from all the possible variations that we determined would work. Wish me luck!!

Thanks everyone! Incredibly helpful advice!! And the photos really help me to visualise the space - so that is super helpful. I'd love to have more storage behind mirrors but our wall has too many braces, and framing so can't do recessed storage unfortunately. Might be able to do storage that isn't recessed (behind mirror). I'd need to look at the measurements. Thanks again!

It is nice for guests to have it as an ensuite but the doors are quite close together and I’m sure they could survive walking a few steps through the living area if it meant a better bathroom foe the people that live there full time. But you know how you live and the priorities.