Hi Gareth,
Thanks for your advice. I have managed to get my hands on a head that's come out of an engine which was on around 50k miles. My mechanic is getting it pressure tested and then, if all is well, skimmed and then fitted. Obviously the head gasket is going to be done along with the cambelt (I'm sure he will use a good quality one) - I'm also getting the water pump done at the same time seeing as though the engine is already stripped down and you suggested it to be done.
I'll be sure to keep you updated and let you know how it's going.. Fingers crossed it'll be sorted soon!