The BSA with frame number (and also duplicated frame number on the engine) WM20.35572 was made under contract C/7287. This was a contract for 17.000 bikes (frame numbers WM20.25001 - WM20.42000). Unfortunately the ledger page containing this number is lost. But from the previous and the next pages we can see that it must have left the factory in early April 1941. The original census number would have been C4352164.