We do not yet know if the seller is the thief. Could be a breaker, could be unknowingly handling stolen goods.
That is my thoughts too. Let's be realistic, if you'd just stolen an E55, would you be listing all the parts for everyone to see within days on a national site like eBay with no effort to disguise (even listing exact mileage on some of the listings!)
The whole thing just seems really strange to me. A relatively unusual car like an E55 seems like a strange choice of car to steal? Not like your old-school diesels and 124s etc going abroad or commercials for parts? And not as though it's some high-value (£50k+) sports car etc?
Being that they are relatively few in number it's not hard to ID parts - which is what has happened now - why would you bother?
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I can only guess it was taken by relative amateurs/toerags who passed it off to a breaker when the novelty had worn off and they realised there was nothing they could do with it? But who would (legitimately) break up an un-damaged mint 73k mile car with no log-book?
Dodgy as ...!