As Dazs 4x4 said

These are good - made by "GATES"......some peeps sell them as "Group A" items at a premium price

.....but if you shop around (motor factors) they are not too expensive at all

Also available on-line from here:

I quote: "O.E. Timing Belts for Cosworth Engines - Says it All!"

http://www.motorsportsuperstore.com/...asp?pc=GATESPG