Just had a looksee at the DVLA website and it appears as though RDV 89N is sitting on SORN somewhere in UK, with the last V5C issued on 19th September 1994. So the old bird has been gathering dust for the past 30 years and is still listed as having "Yellow, Vehicle colour"!
As for "Where? it might be, I'll leave that to you, but you could try the DOC GB to start with.
Student eh? 1976 was when I acquired my 1974 450 MKIII having sold my 1953 AJS 18S and spent weeks felling SS thinnings for pulpwood, so that I could purchase it for cash and the start of my O.N.D. middle year in the I.o.M.

Good health, Bill