Greetings Duncan,
It would be very worthwhile to get the photos you have scanned and recorded here.
The Singer nine in the mud is Driven by Ralph Watson but is his Four seater, rather than the Le Mans which was his second Singer. Refer here, pages 6 & 122/6. ---
http://ralphwatson.scienceontheweb.net/
The NSCC mud plug was officially titled, “The Winter Trial” and was certainly a fun event, but it comprised a serious component in the clubs yearly calendar, with a still existing designated trophy. It was Ron Roycroft’s habit to specially acquire a Model T Ford each year in order to win the event. However on the last occasion, he ran second to me after I attacked the final hill at maximum speed in my very versatile ACV8. LOL
Them were the days. Trevor.