Craig, you might want to try Gunze acrylics. Very similar to Tamiya, but with colours pre-mixed, ie all the key RLM colours, and thin perfectly with Tamiya thinner.
Best supplier in the UK is just down the road to you in Derby, see link below:
http://www.shopcreator.net/mall/modeldesignconstruction/
I've no links toMDC other than as a very satisfied customer.
Karl