Andrew
More food for thought
Having made the suggestion that the truck may have been a 'Headquarter/Survey Section' vehicle, I have since found this photo showing a timber bodied vehicle used by the LRDG. Note the two machine gun pedestal mounts which would indicate that it is a 'fighting vehicle'.
http://www.lrdg.org/historical_photos4.htm
http://i135.photobucket.com/albums/q...ps6afd039c.jpg
Note that the vehicle closest to the camera in the photo below appears to have the same timber body with the deep square cut wheel wells. These trucks are New Zealand patrol vehicles, 1943.
http://natlib.govt.nz/records/228469...e+desert+group
Note that the spare wheel is in same position. The tire is supported through the use of a shaped timber block mounted to the running board.
http://i135.photobucket.com/albums/q...ps397ff2c1.jpg
Interestingly, this truck has exactly the same setup. Note also the timber tool/chain box that sits under the tray. Compare it to the wartime photo. Same position and size. Note also the steel upright corner bracket of the rear body is the same 'unusual' shape with the outward facing blade as well.