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.

Before replacing your curtains as this can be quite expensive for such a large window, if they are in good condition, add a band of extra fabric to the bottom in what ever suits you, your existing curtain track can then be moved up to the ceiling for good looking full length curtains without the large round eyelets, could save you a lot of money, I would look at replacing/removing the sheers cheers

Do you want modern or classic look. China white for classic it changes from grey-to light greenish colour I have it in the same facing room, or for more contemporary try Big white from Taubmans , it's a white with a bit of grey in it very soft. With your grey sofa I would stay away from darker greys and north facing room can make it really dark in the afternoon.

what a great looking house...could you have the dark colour around the front porch, front of the garage and the alfresco walls (where it's shady in the photo) and have the rest of the house white or surfmist?