Normally it’s around 1/3 of the wall height, maybe fractionally higher. This image looks good Most of your imspiration pics have wallpaper, would you consider that? Coving may look good depending on the style of the house, I don’t think it’s necessary in a loo though How do you intend to deal with the boxing in of the pipes? Could you increase the boxing in so it’s the width of the wall (hopefully!) just above the sink? You would then create a shelf for things, this is the best pic i could find minus the white sill!

My grandparents did this by themselves everywhere with plaster as it ”cottigified” everything, I guarantee that it is cheap to do yourself with plaster, as my grandparents chose it over wall paper, and they always chose the cheapest way because my grandad knew how to get on with what he was told to do so he could get back to his Clan pipe tobacco and a Whyte&Mackay, my forced mission in my life time is getting back to lovely flat walls, we are in a perpetual decoration argument with our ancestors . At least there is still Whyte&Mackay

I have panels purely because there’s no dirty grout to keep clean. There is a large assortment now available. I have Bushboard. It makes no difference to the temperature of the room whether you have panels or tiles. It sounds as though you need a bigger radiator or perhaps consider underfloor heating.

Hi Sophie, The headboard you’ve chosen is really lovely. The stripe is quite delicate, so I’d be inclined to keep the wall colour soft and understated to maintain that sweet, calming feel. I’d probably avoid anything too strong and instead opt for Farrow & Ball Pignoir. It will pick up the warmth in the headboard beautifully. It’s a very pretty bedroom colour without reading overtly pink or purple. Sorcha