[David_Hayward (RIP)]

That's apparently a MVA company in Hedge End (Tidworth) Depot in Wiltshire [Salisbury Plain]
Source:
http://www.army.mil/cmh/reference/No...TS/OD/OD13.htm

In 1942 there had been two Ordnance branch depots, Tidworth in the Southern Base Section (SBS) and Rushden in the Eastern Base Section (EBS), and Ordnance sections in six general depots-Ashchurch, Taunton, and Hilsea in SBS and Barry, Moreton-on-Lugg, and Sudbury in the Western Base Section (WBS). In 1943, as labor and materials became available, branch depots were activated at Warminster for combat vehicles and at Castle Bromwich for tools, and Ordnance had obtained space at two more general depots, Coypool at the port of Plymouth and Wern near Liverpool. Five vehicle parks had been added to the six in existence in 1942. This amount of space had been planned for theater reserve stocks in BOLERO and was obviously inadequate for OVERLORD
The program for the advance shipment of T/BA and T/E matériel alone, which went into effect in July 1943, entailed a sizable expansion in storage space: for example, the preshipped equipment for one infantry division included 2,089 vehicles....

...Maj. William R. Francis, who went to Treforest and studied the British Austin Motor Works assembly operation. "Yank ingenuity," as he expressed it, did the rest. With the help of two capable assistants, M. Sgt. Leroy Bell, shop foreman, and Pvt. George Phillips III, a time and motion study expert, he got the assembly line in operation by 18 August. Production rose when three newly arrived depot companies and the 497th MVA Company made a second shift possible. In the first three months of operation Ashchurch assembled 5,000 trucks.

On a smaller scale, Ordnance that fall began assembling 21/2-ton trucks at Taunton and lighter cased vehicles, such as jeeps and water trailers, at Hedge End (Tidworth) and eight other depots and vehicle parks. Between May and the end of December 1943, Ordnance troops accounted for about 43 percent of the 60,70.3 general purpose vehicles assembled in England. But this kind of work began to slacken toward the end of 1943 because the cased vehicles of the most wanted types were not arriving in sufficient numbers.