I've got a sneaky feeling that the K6 was also used as a military version of a machinery wagon , used to repair battle field tank & armoured car etc. casualties & engine rebuilds in the field out of the battle area ..it would have had a change wheel lathe in it too . There might have also been a Morris' one tone gantry crane for the same reason
You might find REME at work pictures using them around October 1942 at El Alamein