Stelland..please excuse my gross ignorance here. I am trying to work around some photographs that I have of the same basic trucks from 1943 and then 1944 to caption them for my book. The IWM official photo by the way is of H 5582702, whereas the one in the top photo is H 5582746.
The 1943 photographs show as you can see F60B tractors + Willys-built 2-wheel GS trailers. Then I have an early 1944 photograph from the same company, in Liverpool as well, and this time [same truck batch] they are 'self-propelled mountings' with the same guns as before.
I am intrigued as to whether there were initially 2 sets of F60B units, one with a G/S trailer with ammo, and the other with the Predictor that connected by cable? It seems that by early 1944 as I said before the Predictors were no longer required and the Ford Bofors trucks were self-contained units. The 1944 Census states that all three batches of the British orders were 'SPM 40 mm' with 'S' prefixes. This reflects the conversion of all F60B trucks left to self-propelled units.
http://clubs.hemmings.com/clubsites/...lk/BOFORS3.jpg
ABOVE: this photograph from early 1944 shows two F60B Bofors trucks [S 5582815 leading] converted to SPM 40 mm specification, less the Willys trailers. A close inspection of the rear truck S 5582667 suggests that the driver's window pane is missing.and there is no left side wiper either.