Hutchie, The Barber book mentions several incidents where German vehicles were captured. On leaving his RV Major Pat Hewlings, 2i/c of 225 Field Parachute Ambulance, tells of a German Staff car driving into their midst and the officers taken prisoner. Later at the Chateau where they set up their MDS there were a number of "small Citroen trucks in various states of disrepair" that were being used by the Todt workers who were captured while still in bed. Sergeant Fraser Edwards of 317 Airborne Security Section along with Rene House captured a German HQ (Chateau Debeds) in Ranville and took prisoner 4 young Germans. They were also pleased to take possession of a German car. While still tying to find their RV the group Major Guy Radmore (12th Battalion Brigade Signals) was with encountered two British sailors driving a German Vehicle which they very nearly grenaded. Major Radmore told them to get out and walk. I imagine there were many others as well. Regards ...
Troopers C. Davies and L. Walden with a German mobile 20mm Anti-Aircraft gun, captured by the 6th Airborne Armoured Reconnaissance Regiment and used against German aircraft they successfully shot down a Bf-109 and Fw-190. http://www.iwm.org.uk/collections/item/object/205202499
Footage of Troopers Davies & Walden near Pont Audemer 00:20 filmed by J.R. Connolly No. 5 AFPU A70 140-8
This thread mentions Canadians using German vehicles: Which allied units finally closed the Falaise Gap, on 19 August, at Chambois?