Hello Martin.
The only David Brown 2D towpath tractor was until a few years ago owned by the late Bill Speake , who was a good friend of mine.
It apparently worked on the Avon and Kennet canal in the 1960s as a general ‘dogsbody’ during remedial works on the canal. I understand that it finished up falling into the canal, after which a veil covered the event. It was rescued and spent some time dumped in the canal yard, prior to being rescued again a few years later and restored, I know Bill did a lot of work on it, I am not sure if he carried out the restoration. Dear old Bill showed it at many rallies around the UK and was a regular at the Dorset Steam Fair, I am not sure who owns it now , I believe it is a serious David Brown collector in the UK.
I may have more pictures somewhere.
Chris Fuller