A lot of the info on various threads is US based, so I thought I'd start a UK thread. Unfortunately I only know of one place to buy, so if anyone wants to help please reply with where you get your supplies from and I'll update the post.
The Invisible Edge: The Invisible Edge - Scales, Pins, Cases (lots more too)
Model Dockyard: Model Dockyard - Brass Sheet and Brass Rod
P.S. If there *is* a wiki or existing thread for UK suppliers, please let me know :)