It's probable that Ross redesigned the Ensar lenses during WWII, they brought out an f3.5 version sold in the newer Epsilon with 1/200 top speed which was fitted to the Commando. The BJP Almanac for 1941 shows German lenses & shutters on only a few top models and stocks must have been very low by then. By the following year no specific cameras are listed but they state that Ensar lenses are of the highest quality.

Ian