Hello Mark and welcome. I met Nat at Box Hill in September and I have to say his bike is a lovely clean bike. I’m sure you will find it a nice addition to your collection.
Engine and Frame numbers
RB Engine# SC05E-200xxxx Frame# SC05-200xxxx
RC Engine# SC05E-210xxxx Frame# SC08-200xxxx
RD Engine# SC05E-220xxxx Frame# SC08-210xxxx
Trev