Iain, remember the V5 only shows the registered keeper of the vehicle, who is not necessarily the legal owner. As Christopher says, the two plates you can see on the car will be the original body number & the trimmed body number, but AFAIK these bear no relation to the VIN.
It is important to establish that the seller is the legal owner & hence can pass title to the car to you. Has he got a receipt for buying the car? Can you HPI check it to make sure it is not recorded as stolen? Remember that he cannot pass on to you a better title to ownership than he holds - so if he has no title (e.g. it's a stolen car) then you have no title even if you buy in good faith. A previous legal owner can come forward & take back the car.
If you have the registration number of the car then DVLA will be able to issue a replacement V5, and that will give you the VIN, it's not too hard to get a replacement VIN plate made up once you have the correct paperwork.
If you go ahead get the seller to give you a receipt for your money, so at least if something questionable comes up about the ownership of the car you have something to show where you got it from.
Tony
<font size="1">1981 TR7 FHC Cavalry Blue
1980 TR7V8 DHC Jaguar Regency Red - sadly sold!
1977 TR8 FHC EFI Factory development car Inca Yellow</font id="size1">
