i third the decision........camshafts rarely break, and if it did, you'd have a rather massive bill - new valves, seals etc. i think hes telling porkies. i would ask him how hes come to the conclusion the camshaft needs replacing!! also get the timing belt done at the same time.
roughly
£55 - radiator (diy time - 15mins)
£6 - aux belt (diy time - 15mins)
£30 - backbox (diy time - 15 mins)
£10 - brake pads (diy time - 15 mins)
and its all a quick 1 hour job to do yourself. buy yourself a haynes and start diy'ing, you're going to be repairing an old car a lot, so your going to need to learn sometime, why not now, save £200. also, £200 @ about £30p/h....its not 7 hours worth of work!