FWIW my 1951 EG Bates has the boss for front lamp on the left hand fork leg but my prewar 'Chater-Lea' has a small lump to stop a bracket slipping down on the right leg. Pre-war Chater Lea braze on bosses and their brackets were offered as RH or LH in the 1938 Brown Brothers catalogue but only as RH in 1951. Stuart Tallack in Silly Sussex