David the thing that points me towards the picture being early1943 and the truck late 1942 production are as follows:
Small holes in the bumper edges, the sequence for these goes as follows, early and mid 11's no holes, very late 11's and all 12's large holes, early 13's large holes, mid range 13's small holes, late 13's no holes.
Absence of roof hatch: 11's none 12cab field mods have been seen fitted with a square field mod roof hatch, early 12 cabs no hatch mid and late range 12's square hatch as factory standard
Early 13's factory fitted square hatch (but not all models, agent 'O's C30 1942 LAA hasn't got one for example. Mid range 13's nothing, late 13's round roof hatch.
The fact that it's a 30cwt would point to it being early in the 13 production run, 30's were limited standard and then phased out of production.
The two blokes (and before any one says it they are not Steve and me again) are in winter coats and there is very little shadow tone in the picture suggesting a weak low sun.
There you go guys tell me I'm wrong
Pete