This may be a bit of a long-shot but could you possibly go down the route of sending off to the DVLA a letter with the £5 fee asking for the previous history of 843 XJ, I do this with every vehicle I acquire........
If you are the owner/keeper of a vehicle the DVLA will send you photocopies of all documentation they have (eg original log books etc) if you show 'good enough reason' for wanting the info...
This may not work though if the vehicle isn't currently on the DVLA computerised database...............:?:
:wink:
'63 Karmann Ghia RHD
'72 1302LS Karmann Cabrio RHD