That looks like a load-bearing wall. Architecturally, how did they make sure the wall could continue to support the weight above while carving out sections of the middle of it?

Before deciding on a colour, don't forget to consider your kitchen cabinetry, benchtop, splashback, etc (and dining furniture)... for example, if you have a classic hamptons (farmer style) kitchen (and furniture) then don't discount a warm white for the walls... it won't look clinical as the warmth will come from the kitchen cabinetry, etc and dining furniture, e.g. But if you have a "hamptons inspired" look with a slightly more contemporary kitchen cabinetry (and furniture), then in my opinion (all nice options above but a bit too beige'ish for me) so I would suggest a light shade of a warm grey e.g. Whichever way you decide to go, try to narrow it down to 2-3 colours, get the small pot samples and paint each one on all the applicable walls as they will all look different at different angles depending on how they reflect natural daylight and the lights at night time... then you may be able to make a clearer decision. Good luck! :)

The vertical blinds MUST go. Sorry, but they are hideous and add nothing. Get some fabulous mid century fabric pattern in some gorgeous colours and make curtains. You can make a couple of scatter cushions also out of this fabric. Then pick out your favourite colour from the fabric to add some plain cushions. If you have gone with the patterned rug option such as asquithoatley has suggested, then just pick out the gentler colour for plain curtains to compliment the rug. Either way then choose cushions using any, or all of these colours. Then you should look for some decorative items in these colours such as beautiful bottles that might pick up an aqua, or some lamps with bases that colour to put on a side board. For the wall I suggest that you look on ebay in mid century modern and see if any wall sculptures attract you. There was quite a fad for enamelled metal wall sculptures back in the 60s which would add some life. Try to find one that also incorporates one of the pattern colours. Susan_66 made a great suggestion with a Howard Arkley print of a mid century house. You might even find one that is similar to your house style which would be fun. Happy hunting. You have some good pieces and they will work well with a bit of fun fabric or rug to link them.

Oooooh lovely to see such great work in my neck of the woods. Pity City of Bayswater doesn't do heritage awards you guys deserve one.