Hi there
It wasn't army issue, but as David said, hundreds of civillian cars were pressed into military service early in the war.
I'd be fairly confident building it as issued to one of the first units in the UK like 1 CID or in domestic service in Canada.
I've built two Heavy Utilities using the AMT 41 Ford Woody.
http://milifax2003.tripod.com/linkfordHU.jpg
Steve