That's a very quick turn round for each owner or plate change.
Excellent question to the seller Dan at least he was honest. Only 6 former owners and a plate change on my 1991 124 Coupe. 115k miles and it runs great.
Previous 1994 SL500, 2001 W210 E430 and 2003 Designo S500 Current 2005 S211 E270
Its £1395 so hardly a financial risk? If it turned out to be a cut and shut you could sell a few bits off it, weigh it in and probably be a few quid up, especially if you were local.
That's not unusual unless the receipts have been kept though?
I just bought a Range Rover with a fully stamped book but not a receipt in sight as previous owner ran through his books which is pretty common in a lot of the cars I have bought anyway.
Shame not everyone is so careful with keeping a proper history.
Also, just a thought but is a head gasket on the service schedule anyway? I guess makes sense to be done at a certain mileage but would that not be circa 100k anyway?