Fred seems to be one of the most knowledgable and comes highly recommended.
Northwest Performance seem to do them for little over £400 however are quite a way to travel.
Could also consider JMS or Rentech, no idea of prices/location.
Or if you fancy walking like John Wayne you could try your local Dealer. On my free health check they quoted me £950 for a cambelt change. Obviously blind bunch of idiots as it had them done 3,000 miles ago.