[Richard Coutts-Smith]

No expert in this field, so I checked out my copy of British Armoured Cars 1914 to 1945 by BT White which showed that the Turret is an "Admiralty Pattern", possibly fitted to a Rolls Royce 1920 Pattern Armoured car. I note the lack of a side door as on the 1924 model
An internet search came up with this one which appears to be the same, with smaller wheel/tyre combo. (pic from the Shutterstock site). Only info was it's listing as Israel British Troops.
HMAC Capetown on the bonnet
The left hand drive shown in the original post threw me, but I believe the image maybe reversed due to the pioneer tool layout being opposite to this one.
I think the huge tyres and wheel arches are hiding the true length of the vehicle?
Rich.