Hi, I definitely think rooms that get a lot of natural light can take the punchier darker colours. For the feature wall I can suggest rockett st George as a place which has loads of great wallpapers. For getting it to work with the dark walls I think it's key to pick out the dark colour in the wallpaper somewhere. Going completely different is likely to be a little jarring visually.

I think a brick wall will look amazing as I love them. I love the rustic orangey reds like the one behind the faceless lady. It adds so much warmth. You could use brick slips instead which are real bricks but much thinner so they are applied rather like tiles. My builder brother used them on a job in a loft and he really liked them and they look like full size bricks. These a brick slips

Hi Lauren, how would you like the room to feel and what styles do you like? For example do you want it to feel dark and moody or do you prefer a light and airy look? For the window you could opt for Roman blinds then to add warmth just dress curtains on the outside of the window to help soften the sharp lines. Hope this helps!😊 If you would like help to complete your room, we are an affordable online interior design company and would love to help you create a room you’ll love! I’ve added our website below if you would like to find out more. www.thelivinghouse.co.uk

Totally agree with Holly's comments. The benefit of all in one colour will be lower costs for decorators as there will be no cutting in as well - so worth bearing in mind too (unless you are doing the work yourselves of course!). I'd go with the Slaked Lime Mid all over - it won't feel too dark once its up on the walls. You'll be amazed!