...can you elaborate on the first 3 letters you mentioned as grey import as i'm sure you have gathered that my australian import ahs its new plate ending with G the first 3 letters being CHJ
I'm not sure what letter sequences the DVLA are currently using as prefixes for 'Age Related' grey import registrations, but there used to be a LOT of 'RYT'. 'RYL', 'RYX' and 'RYY' prefixed cars running around in the London area, for example. One of my close neighbours even had a USA-import Porsche 911S with a number very close to one of mine.
But what's the reason for your asking? Do you not know the history behind the car, or is it just curiosity? If it's the former, then paying the small fee to the DVLA for a V888 search of pervious owners and any importation history got me the answers to a few questions for my own cars, and I'd recommend it.
Technically speaking,
no S30-series Z should be issued with a 'G' suffixed plate by the DVLA as an 'Age Related' number, as I've alluded to above. The plain fact is that the 'G' suffix applicable dates ran out on 31st July 1969, a full three or months before any S30-series could feasibly have been sold to the general public in Japan let alone anywhere else. In fact, we have data from Nissan Shatai ( the people who actually
made these cars ) which shows us what cars had actually been built before the end of July 1969, and
all of them were factory pre-production prototypes and production prototypes. I'm fairly sure that your car will have been built in 1970 at the earliest anyway. The earliest feasible correctly-issued suffix for an S30-series Z would be an 'H'.
All bets are off when a plate is actually a 'vanity' / 'personalised' plate. You can put an 'F', 'E', 'D', 'C' or even 'A' sufffixed plate on a 1970 Z retrospecitively if you want. The point is that UK registrations are not reliable ways to date these cars. I wouldn't bother taking them seriously.