Thanks guys to all the well-wishers and those giving sage advice of the tangible chances that this is bogus. I hope it is clear by now from my posts that I am aware of the risks here, but am consciously taking a chance on it being legit due to the payment protections due diligence I did, and due to the seller not being some fresh fish on Ebay. If I need to go through the rigmarole of getting my money back with Ebay and/or my credit card company then I will do that. I am a determined and persistent guy.
He also replied to a mail within 3 hours to tell me he will send it by tracked and insured delivery for the full purchase price, so at least it's not a communications blackout.
Watch this space for if it goes well, or of course if it goes south to hell and back.