I have examined this machine, and can state the following without fear of contraception: The cases are 1947 rapide or 1946 ditto because the "MADE IN ENGLAND" is stamped in,not cast.The machine was seen at the 1983 International Rally in Victoria,and Dave Hills remarked that the numbers were suspect.At that stage, the UFM was recorded as being the same as the RFM.According to my memory of early machines I have seen,the mating numbers may be correct on the crankcases and may give a clue to the machine's origin; one would have to refer to the Machine Registrar to confirm this.The engine number was possibly misread at some stage as 6185 by which it is identified in later Section records.Due to the roughness of the stamping/crankcase area this may well have been a forgiveable error. The "B" at the end of the RFM number is also dodgy.