I've just got a 760x760 shower and it's fine for us. The room is 327 x97 (they must have lost a fair bit with tiling and plumbing). My previous ensuite was a similar size with the same size shower. We fitted our old ensuite and the priority for me was a really good shower rather than a teaspoon of water over your head! I know you may look a bit mad but you could go to a showroom and try getting in a cubicle! Or see if any friends have the same size as I think you'll need the extra space for getting ready but it does obviously also depend on the height and build of your family

Thanks active builders, I thought 1.8m depth for the wet area - assuming bath is 80cm wide that leaves 1m depth for the showering area, but then that only leaves 1.2m to fit basin and toilet, which I thought might be a bit tight? We don’t really want a small basin as this is the main bathroom. My other option is to have toilet and washbasin opposite each other in the 1.2m run, but then this leaves a 80cm gap between toilet and washbasin and not sure if this would look a bit cramped?

You can get trays that can be cut to size that would fit the space perfectly, a company we use is called fiora https://fiora.es/en/home/ you can then just add a glass panel and leave yourself with a 550mm/650mm space to walk in. Alternatively you would have to go for a 1700 enclosure but not to waste space you could stud the wall out and create some recesses in a stud wall behind. I hope that makes sense.

I'm just about to buy a hour with EXACTLY the same issue (and exactly the same floor plan!!!) I have looked online at turning the bath around to go under the window & moving the toilet but it seems like quite a big job so I'm wondering if I could move the bath to immediately inside the door and the sink up near the toilet?!