Head off, new valves, head bolts and gaskets, head back on. Easy.

Gasket set is about £40 and valves are about £4 ish each. Cambelt is about £15 from Ford.

You can have it done in an afternoon.

If you're a beginner at this stuff, it will take longer so don't rush and ask for as much advice as you can. If you're unsure about swapping valves over, ask your local engine machineist to do it for you (and fit new valve stem oil seals).