I phoned Nissan this morning to find out the actual build date on my 240z as it was first registered in 1974..mr parts man said no chance they can help as they dont use slides anymore..
"ld vehicles constructed before 1 January 1973 (historic vehicles)
If your vehicle was constructed before 1 January 1973, you could tax it in the 'historic vehicle' tax class. Further information can be found on leaflet INF34."