A friend of mine who lives 'oop North asked me to collect a cylinder head casting which he had just bought & paid for from a guy fairly local to me.
I duly collected it and was amazed to find it to be a brand new and unused 12G295 head. I never thought I would ever see a new one again. It just needs valves and springs.
I don't know how much he paid for it, but I bet it wasn't cheap.
So such items can still turn up.