I can see some large fluffy Folaki (sp?) style rugs in here. They come in room-size large rectanges as well as the more common little ones you can get at IKEA. Add a bit of glam with some mercury glass candlesticks, some art, maybe a sculptural piece or even a tapestry, and a teak bench, and it will be fantastic. I would go for just a few really bold and big pieces, mostly white and chrome. I would hold off on painting until you add a rug and some accessories. I like the contrast and it won't looks so stark when more stuff is added. I hope you have plenty of towel racks on the wall we can't see! Nice thick white ones would work with the rest.

I had to settle for a shower for years and years because the place we lived in only had a shower although my showers are deefinitely not a three minute person, more like 15min ha-ha I too decided on a spa bath in our new build, one that is big enough to fit two people but is simply a bath shape and I'm finding it hard to get myself back into baths because of being used to a shower for so long but I don't regret it either. I used to read the paper in the bath back when papers were what was around back then and I do miss that ha-ha

The choice/decision will be different for different people and different contexts, comes down to personal priorities weighed up against cost. Is the priority the function or the aesthetic? Sunkens practically need to be set up in a particular way to achieve a unique bathing experience, more like a spa/pool - not ideal for a standard family I would guess, can have a tendency to look better (ie "cool") in pictures than working that well in reality. Free standings always look great if appropriately scaled to the space and can achieve the illusion of more space in the bathroom, but can be an issue to clean behind and also resolve suitable tap ware/filler if you're on a budget.....In hob's are most practical for kids and functionally they probably win over any other options particularly if detailed with a reasonable ledge width/surround

For storage, I used a mirrored lift up cupboard door above the sink area in my very small ensuite with some success. We put power points inside the cupboard too - it was a very good place to have them as the door lifts up & is out of the way. I also used some of the wall space to allow slightly deeper shelves, without the cupboard jutting so far into the room. The cistern was recessed into the wall cavity, (in our case below the window) & it worked well to save a little space in the room. Photos are not very good, but I hope you can get the idea.. It worked very well. The ensuite was 1mx2m. We use vertical towel rails. They're really good & very compact, but do make sure the electrician installs them up the right way. They work on the heat rising principal & do not work well upside down as ours were installed!Hope this is helpful. Good luck.