As is with anything in life you live and you learn.
Bit late now but next time you decide to buy a bargain make sure you take someone with you who has a compression tester. If the seller refuses to let you perform a quick compression test then walk away.
Also try some of the links in our links section for a replacement part or a specialist cylinder head centre such as
Based in Cornwall but they offer next day delivery nationwide.
Oh and welcome to the forums ;-)