well, a little update:
I dropped him a message via ebay yesterday, letting him know that Big Brother is watching. Here's his reply from today:
think you need help mate had it checked out and it is indeed an a10 head grow up idiot
or man up
- lin12340
What a nice and competent person, one more thing to report to ebay. Not that I feel underrated in my manliness (at least I for one AM man enought to bow to my mistakes and admit when I'm wrong), but I don't like being called an i***t when I know that I'm right and even got the report of an impartial expert to prove it.
Paypal has responded, they are investigating it already, so hopefully he'll soon be banned. Somehow this starts to get amusing (well, kind of), since I don't take such people seriously anyway...

I asked him a question re diameter of combustion chamber
no reply as yet
Last year before I bought it I asked him about the number on the manifold, never got a reply as well. Now he states you couldn't read it, well, have a look at my photo, mate!