I worked at the BRS Douglas Group at Port Dundas, Glasgow (Depot Code BB) in the late 60’s/early 70’s until the depot closed. The first artic unit (24tgtw I think) I had there was an Atkinson (Not familiar with the models but these had a single headlight) with an AEC engine, it also had vacuum braking for the older trailers as well as air braking. I can’t remember how many we had had, somewhere in my desk I have a list of Douglas Group vehicles that John Mollett of Leeds, a BRS enthusiast, gave me and I’ll look it out.
When that old Atki went I had a similar one which did not have the facility of vacuum braking.
AEC was the prominant engine in the lighter vehicles including my 3rd vehicle, a Seddon 13:4, we also had a Guy Big J on the Stranraer Trunk with a tilt for Containerway, this also had an AEC engine.
We also had a 6 wheel Foden flat which originally was in the fleet of Gavin Wilkie of Glasgow, that firm was absorbed into BRS/Pickfords.
Hope this information is helpful
Alex