I'd do a full HPI check and probably speak to the DVLA about it before parting with any cash.

has it been sold on without being swapped over to the new owner, there's another V5 somewhere in the new owners name ? If it's one previous owner then it's on it's second owner. Does the issue date on the blue V5 match the date of first registration ?

could be a legit reason or it could be otherwise.. maybe that's why it's so cheap for an FRST in great order..

2p