To this date, the only info "real (?)" that I have on it, point to being a Albion Valkyrie, PW65 chassis (?), maybe with a Cowieson body (the only that could I find with rear opening driver door) as seen on the link bellow.
https://www.flickr.com/photos/iainrobbie9/8507595746/
Being a Albion, two other possibilities are a Valiant or a Victor, but I didn't find a good photo on that direction, some with a dated body, other with a more streamlined one.
https://www.gracesguide.co.uk/Albion_Motor_Co:_Buses
Many images dont show the "right" side to see the drivers door. Other clues, as the windshield inclination, the wheel rims holes, were found in many buses f the time. I think it is from the 1930-36 timeframe, and locally made, as I have seen other "things" used to the same purpose.
https://media.iwm.org.uk/ciim5/30/29...584.1584549594
source:
https://www.iwm.org.uk/collections/i...ject/205186688
One point is the absence of the fuel tank gas cap fairing, that is usually on this side, indicating that it is on the other. A problem is that were many body builders, and the transport carriers purchased the bus chassis (with engine, steering, etc) from manufacturers and the bodies were sourced from these builders, and so there were identical ones in different chassis...
Cheers!