I love those long floorboards/wood-look tiles and they are the feature so you wouldn't want something too busy on the walls... personally I would go with a larger format say 300x600 rectified edge white tile with a matt finish for the Hamptons look... what's your vanity?... a timber one would tie in nicely with the floors and all the white... very Hamptons :)

also will give illusion of a bigger bathroom if you use bigger tiles ..I used small ones on one wall as feature wall and larger ones on other walls ..

because the water could seep through the joints between the new tiles and sit between the two layers and affect the seal and also raise the height of the floor and affect the slope to the waste outlets..but, why do you want to retile if you're not using the bathroom??...for immediate resale consider bathroom wall to wall bathroom carpet, new wall paint, new vanity, taps and light fittings which should also be cheaper than tiling over the top and, if it's not allowed by the body corporate, it will be a risk to future sales as it should not satisfy a proper building inspection

Yes thank you for your thoughts. the room is 2.8 (with window) vs 3.4m. I do find it a bit annoying too as I don't like that you open the door and see straight away into the shower (though I'm certain the door would have a lock). I'm sure they lined the bath up to be with the window as visually that looks better, but then I find the space at the end annoying. I like the alternative drawings (I like three of them lots!) and I had been considering an drop in bath built wall to wall rather than a freestanding but also finding it frustrating to find a really nice supportive bath and there are less drop in baths than freestanding around at the moment which is a bit annoying. Thanks Anna for the picture, that helps as that looks good (though we would have more space at either end, 50cm) and I prefer the look of yours with some space but not as cavenous... I think I might have to have a talk with my husband as we really need to work out what to do!!