Geoff, you have duplicated your posts here. Suggest you close one down or it can get very confusing. Sorry I don't know the first thing about wallpaper.

Yes, I had noticed a lot of pics on Houzz, that's what gave me the idea! I certainly wouldn't put it IN the shower! We have a tiled shower, but the tiles only go as high as the glass surrounds, so there is about 30cm of painted wall above the shower, which is the part I was worried about with steam etc.

I'm sure there's a lot of information out there thanks to a quick Google.

There is a lot of paste and size residue still on the walls. Washing and scraping helps but it still feels like it's there. Would a good sanding be sufficent or do I need to wash all the paste off before painting?