If you don't have a local branch of Game, try Electronics Boutique. They're part of the same company and price them the same.
Then games came down from £10-15 each to £8, wish I'd known they were going to do that when I spent £120 on games and accessories two months ago...you can get spare controllers and SCART leads as well.
Interesting note: The box for the Jaguar controller has a note on the bottom saying 'Works with selected games on 1040STE and Falcon030 as well'.
Who says they stopped supporting the ST and falcon when they started making the Jag???