A total of 1706 motorcycles were sent to Russia as lend lease in April/May 1944,most were BSA M20s (around about 900?)the rest were Velocette and Matchless models,photo below is of one of the Russia M20s taken in Moscow,has yours still got the knee rubbers the same as this photo.
The most known lend lease bike in Poland is WLA. 1700 bikes from England? Or all? I think we have now few hundreds lend lease Harleys in Poland. I havn't original knee rubbers. I remember one, but it was lost when I was young. It was smaller and thicker than standard rubber. I don't remember BSA logo on it.