Browsing through a book about Jeeps in British service during WW2 I came across this photo of a driver clad in a shearling jerkin. I wouldn't mind something similar...
I remember when surplus stores used to be piled high with ex service jerkins but I'm not sure I recall seeing one with pile like that. Just so happens that I've got a rather minty Belgian example that I wear every now and again.From the look of the buttonholes it seems to be a standard Army jerkin with a shearling lining and a collar. He might well have got it modified himself somewhere.
Most of the WW2 ones on sale are a bit sad now but you can still buy very good Belgian army versions in unissued condition. They have brass buttons but they can be changed and are otherwise pretty identical.