Morris-Commercial C8 Gun Tractor body id please?

[David_Hayward (RIP)]

From an anonymous book it seems that the truck H 5847572 had the sheet metal sides, doors tailboard and toolboxes removed. The tractor was then loaded with boxes of 17-pounder Armour Piercing ammo, with boxes containing two rounds each. During Operation MARKET fifteen boxes were carried per tractor. However the photo published of the rear view shows no room for the crew! As I said this was a rebuild or batch of M-C C.8/AT Mk 111 No. 5 bodies with demountable rear bodies. Could there have been a specific batch of Airportable versions failing the rebuilds on the C./8MG and C.8/P trucks which were old hat by then?