Mk1 Golf shell

Around 10 years ago I had the chance to buy a mk1 shell which was going to be a show car for a garage near Edinburgh.  They had skimped on a few bits so I have redone rotten inner lips and a few other bits.  The vin no. is on scuttle and I have the tags from front panel.    Would anybody know if I could find it's original no.   I have tried vin2reg but they had no record.  Would vw uk have any records?    Would I just be better getting a certificate of conformity and then applying to dvla for an age related plate?   I am planning on building it as a mk1 gtd which I am going to fit a mk2 turbodiesel engine and box.   Because I am modifying it would that cause problems when it comes to get it registered?
       Any help appreciated.

I bought fairly recently a shell with no number plate, had the vin plate and a document from vw stating build date etc..Contacting dvlc they said i had to build it up into a complete running car and then (assuming after an inspection) i could apply for an age related plate. However because i wanted to build a modified car i thought this would mean a q plate (did not confirm with dvlc) which i didnt want so sold shell on....