The Harford series were specials built for trialling by T.C. (Cuth) Harrison of Sheffield who was also a racing and rally driver (he raced an ERA and won a Coupe des Alpes in the Alpine rally).
Being a Ford dealer, not surprisingly they were Ford based.
Another photo of SCM and JAC in Harford III OWA 523 appears in the March 1952 Motor Sport. I think the Kitching Trophy Trial was held in February, so a 1952 date for the photo in this thread seems likely.
Elsewhere on the internet there is an entry for SCM/JAC in a Harford for the 1948 Kitching Trophy, but I don't believe it.