Lovely print. I had a peacock feather print and I had a colour called glacier Grey behind. Think it was Wattyl . Again like your other walls it is a greenish grey but darker. I also had my prints on a charcoal wall..loved that too. As you said the picture ties in with the chairs and now it's not necessary to add more matching colours. I'd buy a couple of sample pots and paint large pieces of cardboard. With the other walls I would consider painting them in whisper white (Dulux) a very universal colour that ties in nicely with all colours.

I think painting the walls lighter and brighter is the right move but don't be restricted to white necessarily - although that would be the safe option and you know for sure it would work! You could introduce a contrasting colour on the ceiling if the walls were white obviously dependent on your furnishings and other colour choices. How about a soft grey or "greige" as an alternative to the white? Finally, you could introduce a dado rail at approx 1m from the floor - painted white the same as cornice and ceiling and then paint the upper and lower sections in contrasting colours of say charcoal on the base and white above or 2 shades of the same colour.

I would definitely paint out timber frames, they in themselves become the feature if you don't…..and I would hope you mean a soft grey! To "hide" skirts and arc's (I renovate and sell for a living) I do them the same colour as the walls but in a satin finish…..you could do semi gloss….a water based enamel works best. Make sure you prep them well though, either a good sand to rough up, or something like ESP. I always thought rule of thumb for a feature wall, paper or paint, is the wall opposite the greatest light source, ie. the wall that gets hit with the most natural light. Failing that, I think it would look lovely on the alcove/bay window wall and do the inset of the alcove/bay window in a contrast….say a soft version of the pinkish hues in the paper??? You seem to have some substantial pieces of furniture, and a piano, so doing the other walls would compete and look overbearing to me. Unless you are going the whole Regency style embossed paper/stripes/pattern everywhere…………...

Both colours would look good with the flooring you plan Is the brick wall staying? The darker shade would balance the strength of the brick colour The white kitchen will make the whole room blend together as it will 'clean' the colours consider how you intend to decorate the area - is the green going to feature heavily elsewhere? (like living spaces?)