Some of Montys vehicles are very wellknown, like the Humber Snipe.
This has been made by Airfix in 1/32:
Others are the Leyland Caravan, this has been made by Wespe in 1/35:
And the Fordson with the mapvan, at least the caravan is available from Wespe, I thought the Fordsson used to be as well:
He also used a Mack caravan, also produced by Wespe:
Apart from these im sure he must have had some Bedford QLRs and this may very well be the vehicle you are looking for. Plus Models used to do a conversionkit for the old Airfix/Italeri/Revell Bedford QL Portee:
Resicast have a very nice full kit of the Bedford QLR:
Several of Montys vehicles, both of the Caravans, the Humber and the Mapvan belongs to IWM afaik and if Im not mistaken they are all displayed at Duxford, photos of them can be find every here and there, just google.