Cam belt is on but the engine is running a bit lumpily - the belt may be a tooth out but I'm wet and knackered so I'll check the timing tomorrow - the feeling in my water is that the head will have to come off though.
As to the new/recon/engine debate - given the facilities here (i.e. the driveway in the rain) then I'd rather swap the head than pull the whole engine out - if I had good facilities then I'd maybe reconsider.
Thanks for the advice - Graeme