Thanks all - our belongings arrive this week so I will have a go at transforming the space with what we have then search for new things to add. We have quite a bit of art with strong yellow colors and also a Tibetian Chest with yellows and greens. Thanks again!

Since the color is more modern, try to stick to modern furniture. But that color could also be contemporary so you can also use contemporary furniture

Deep gray and all the other accents in silvery old wood and cream. This will add drama, allow the other elements to bring ion light and set off the concrete wall as a true feature. If you want light instead of drama, then go for a very pale beige stone. It will echo stone colours in both the concrete and rocks...

The blue is awesome (grey is too trendy)! The reason it stands out to you is perhaps because it's the only real colour there. Bring in the blue in a window treatment, a small appliance that sits on the counter, a pretty tray or area rug. Also, it is more appealing often if there are more than 2 colours - so right now you have a white and blue colour scheme - bring in red or orange or fushia - something from the other side of the spectrum (like you did with the yellow flowers but in a more permanent way)!