Following on from Ian's Post (We must be getting good as the register score is 7 cars already noted out of 8):
S1 FKJ 420V.....Grey rather than White? .....Early Press Car at Launch......Reg Date Aug 1979
S1 FLJ 418V.....Red, ....one of the same 5 or 6 Early Press Cars at Launch.....Reg Date Aug 1979
S1 KLK 577V.....Red.....Reg Date Nov 1979
EIW 590.....AH Ha! this is new to me.....Not found on DVLA either, so I'll note it as a Silver S2, probably scrapped.....

S2 UKL 965X.....Blue or Silver? Been Both? (appeared as non Elford, then as an Elford). Reg Date March 1982
S2 RKK 326W....Red, Reg Date April 1981....Believed to be the 1st registered S2
GSL-SE CVV 30X....Red....Reg Date Oct 1981.....At auction at Duxford 2003, Believed to be an Imported Car.
Sadly none of the above seem to be surviving now.