keep your eyes open on ebay and focus forums for 2nd hand bits, bargains are to be had.

this american store has alot of focus zetec tuning parts much cheaper than UK prices, and the dollar is very low, and they are quick shipping to the UK:

http://focus.c-f-m.com/

even with import duty its much cheaper than UK prices. they have performance cams for like £180 a set. compared to £450 for kent or piper cams from the UK.