Early 11 cab 15cwt's
 

Found this photo while browsing the IWM site

REFERENCE NUMBER H 13892

PHOTOGRAPHER:
Puttnam & Cash (Lts)
War Office official photographer
TITLE:
THE BRITISH ARMY IN THE UNITED KINGDOM 1939-45
COLLECTION NUMBER:
4700-37
PERIOD:
Second World War
DATE:
12 September 1941
ACCESS:
Unrestricted
COLOUR / BLACK & WHITE:
Black and white
TYPE:
Official photograph
DESCRIPTION:
15-cwt trucks, carriers and motorcycles of a motor battalion in 6th Armoured Division, lined up for an inspection by the King near Brandon in Suffolk, 12 September 1941.
THEME:
Search for more records about British Army 1939-1945
LOCATION:
Search for more records about Suffolk, England, UK

Not sure if they are Fords or Chev's :thup2:

It's not the earliest of the 15 cwts since they have the metal 2B1 boxes so they'd be equipped with the cab vents. They also have the seat backs over the wheel wells which makes them the Pers 2 versions.(personnel carrier)
They all seem to have the same roll of stuff on the push bar too.

Assembled by...?
 

These could have been assembled by GM Ltd in Bamber Bridge if Chevrolets or by Ford at Ripple Lane say.