SABTVR is the current DVLA issued VIN number prefix. I found that out after doing a bit of digging into my cossie puma as it had an SABTVR vin as it was built from a new shell.

Iain, I agree that many of the garages have probably done it wrong by stamping in the old vin. Unless theres an exemption for manufacturer rebuilds in recent cars in such cases.

It was commonly done on rally and motorsport cars too and often for many non-works cars you stripped a donor vehicle for the main parts. eg the s1400 and s1600 pumas you used a donor vehicle and got a kit of parts off ford motorsport to build the car including a new shell. I guess in theory if you had a receipted rally car kit from ford or similar, you could register it as a kit car/amateur built vehicle although i doubt many were as i suspect the easiest route possible was taken to get the MSA logbook.