I believe a light grey would look nice behind the blue in the map - it needs to be a perfect shade of grey as grey is hard to achieve. Possibly experiment with various colours - I usually paint on board using sample pots first then hold them up in large sheets to see what suits the area... This gives you an indication of where throws of light will capture the actual colour and which shades suite the room without having to paint on the walls. The board base colour generally needs to be as close to your existing wall colour to achieve the closest match.

Love the armless sofa-bench! Try using it in the center as a "cross-linking" piece between the sofa and chairs. That way people can sit on both sides of it, conversing with the sofa people and the chair people. Put the chairs where it is and use the side table from the left of the pic, or the one with flowers, between them. You'll need one huge rug to anchor the space or two smaller, and very similar ones, to put on either side of the blue sofa-bench. The other two side tables are too tall and too short for your seating pieces, so ditch them. Use your coffee table between the sofa and armless sofa (18" away from each of them.) Here's a chart for judging table and lamp heights as you'll need to work on that for balance. Please try this arrangement, and post by commenting and using the Attach Images button to add pix of the update. We'll tweak it on out from there.

what colour on walls if whole cupboard is of dark purple

Consider Grey or white. U could also use geometric or any pattern in mint green