As far as I know the C15TA was not used by the Canadian or British Army as a 25-pdr Gun Tractor. Except for emergencies, maybe.
The Netherlands Marine Brigade did use them as such during the Indonesian war of independence from 1945-1949. Possibly this was the inspiration for Harry Bruin to use it as such, even though his C15TA is marked up as a WW2 Canadian vehicle.
Source: Netherlands Army image bank -
https://beeldbank.nimh.nl/foto-s/det...a-2a8b55b09c62
