I'm sorry there is such a delay in the UHB I sent it in to be posted in the section with other Rover/Ambulance documents. But nothing has happened yet.
Relevant parts manuals for the parent vehicle will list if it includes the ambulance amongst the variants. There was a specific supplement for the Marshalls ambulance body for Rover 9 & 11 in Army Code No.22108.
There was no repair manual as such for the ambulance, or indeed the parent vehicle. Some limited repairs were in EMER WHEELED VEHICLES Q 024. But these are a complete mess with odd bits of Rover publications wedged in flitting from Series 1 up to Rover 11 often not differentiating what model is being covered.
Most of the EMERs are modifications & miscellaneous instructions. The EMER ambulance suffix was originally /7 but changed to /2 for Rover 9 & 11.