Hi! Here is a product called tempaper (temporary wallpaper) that is easy to install and would look great in your area: http://deciture.com/shop/decor/home-decorators-collection/bella-tempaper-wallpaper/ http://deciture.com/shop/decor/home-decorators-collection/damsel-tempaper-wallpaper-collection/

Btw happy to spend a bit more on quality wallpaper, as I'll only need a few rolls.. the wall is 4m long

A niche would be a good way to add some drama without infringing on your circulation space. It doesn't have to be deep to be effective. You can do one simple vertical rectangle, and line the back with a mirror, or add some colour with paint, wallcovering or wood. It would be great if you could also add a recessed light fixture at the top. The attached images are perhaps too busy for your situation, but it gives you a good idea of what can be done. Good luck!

Probably the light catches the wallpaper in a different way than the paint on the wall, so the cream paint didn't seem to work as well as you'd hoped. It's tricky... Maybe if you painted a swatch of the right green he might learn to love it?