Dulux Colour mixing can scan any colour you want and make it up into a paint. Most B &Q stores will do it and its free. I would recommend Rum Caramel 4! I have a colour scheme similar to yours and it works brilliantly - it's neutral but not bland, adds a bit of depth of colour and is very restful too. The terracotta tiles will be a strong,warm colour and fairly dominant in the colour scheme so you don't want any colour that will compete with it and therefore possibly clash. Your paint doesn't have to be specifically kitchen/bathroom paint, a soft sheen or silk (if you want more reflection) would be perfectly suitable as both are washable.