There was a recent survey carried out by the FBHVC seem to declare that a vehicle thirty years old or older has historic potential. The survey was complied as the result of contributions from all areas involved in the enjoyment maintenance and repair of historic vehicles in the UK.
It seems there have been changes to copying and pasting URLs/ internet address links. I copied the link to the vid and posted it below though it like others now shows up as a line of text. It may take you to the appropriate page if you copy and paste the line of text below in your browsers address bar, you may get there... I hope.
2020 Research Result Headlines | Federation of British Historic Vehicle Clubs (fbhvc.co.uk)
Perhaps the more web aware amongst us can post a simpler form of access.... please..?