I was a bit puzzled when the rarity of this car was mentioned, as I know of four +4 DHCs here in the wilds of British Columbia. A closer look revealed that there is a distinction here that was not made clear during the programme. This car is a "SnobMog", the Four-Seater version of the DHC and a much rarer beast than the 2-seat version.

Tom Morris
1972 Plus 8
1932 Super Sport "Beetleback"
1961 Morris Minor Tourer
1972 Triumph T120V