[David_Hayward (RIP)]

I would guess spring or winter 1943. The F60L chassis were to S/M 6043 which must have been a 1943 delivery at least. That said some of the shots are of Diamond T 980/981 tractor units with open top cab that came in in August 1943. I would therefore suggest winter 1943? I can date it further because the last C30 that I know of was manufactured October 18 1943 to S/M 6051.
Whilst on that point, I just noticed that officially the S/M 6051 trucks were as follows:
L 5584483 to 5585063 SM 6051 LORRY 3 TON 4 X 4 WIRELESS (HOUSE) as per IWM PHOTO KID 3042. However actual trucks show that they were definitely C30 trucks! The last known C39 chassis were:
L 6178634 to 6178673 SM 6447 LORRY 30 CWT. 4 X 4 TELEPHONE CONSTRUCTION AND MAINT.
These must have been assembled in 1944 I suggest.

As to Ford F30 British orders they were sparse! These were the last known candidates, otherwise the chassis-cab in the photo was a Canadian order:
H 5327001 to 5327600 SM 2487 Tractor 4x4 Lt AA
IWM PHOTO KID 1968 C29QF F30 A/A VARIANT was the last known one but perhaps this was a F30:
L 6189700 to 6189705 SM 60? Lorry 3 ton 4x4 Derrick which I had believed was a F60S in absence of any other evidence