It's in the sticky in the New Members area:
"Our simple rule of thumb is that the model of car (rather than the owners specific car) must have been in production before 1980, ergo a mk3 capri from 1987 qualifies but a mk2 Fiesta from 1983 does not. Therefore on this site, whilst we acknowledge them as classic cars, we don't class RST's, SafFs, Cossie 3 doors as Old Skool."