I saw J2 4213 at BMHT in UK during June 1998, ex Frank Carter. Was on loan from R H Evans. definitely Frank's car even has the NZVCC badge on the front. I also saw this J2 in Howick when Frank owned it.
I was acutally at the BMHT in Sept and checked this out after you passed the same comments on to Geoff (I was quite excited), but alas it isn't J4213 the chassis number is completely different. And the Triple-m Register Year book I had access to at the time confirmed it was also not Frank Carters Car. I have scans of the year book and the details of the BMHT car, it is Ex NZ but left NZ much to early to be Frank's.