Background: BMW’s 320 is quite a rarity among between-the-Wars machinery from the Bavarian manufacturer, having been launched in 1937, with some 4,200 examples produced before it was replaced by the 321 in 1938.

Based on the preceding 319, the 320 was built on a shortened 326 chassis and featured the 326’s 2-litre straight-six power unit with 4-speed manual gearbox and suspension – independent at the front, live axle at the rear – carried over from the 329 (which car the 320 closely resembled, though being smaller and less expensive).

With 45bhp from its smooth six, the 320 was good for a top speed of 65mph and this high performance machine was well regarded for its road manners and handling, as well as its quality engineering, fine finish and good power-to-weight ratio.

London-based Frazer-Nash were the BMW importers for the UK (as well as producing their own distinctive brand of sports cars with their chain-driven models) and all BMWs sold in the UK during the 1930s were referred...