Probably not far off, Steve, although there could be some LHD cars registered in the UK to muddy the waters, I suppose. Of the 118 RHD R75V8 saloons, 14 were not originally destined for the UK anyway (Malaysia, S. Africa, New Zealand etc.) which leaves 104 for the UK. Some of the 14 "non-UK" may never have made the intended destination, or been re-imported into the UK. On the other side of the coin, some RHD cars may be residing abroad in between times like EricLC's car! 2007 Q4 show about 90 total registered, and we know of a few that had not be registered at that stage, so about right-ish?
If that is roughly OK, I suppose you could assume that current figures indicating around 70 R75V8 saloon cars still surviving in the UK, would be about right?
David