According to [Broken Link Removed], referring to motorcycles, 'Machines first used before 1 April 1986 must have a stop lamp that operates from at least one brake control.' So, if that's correct – and I have seen it elsewhere – in the UK all of our Commandos only need one switch. Perhaps front switches were fitted (e.g. on BSA singles from 1967 onwards, according to my manual) to meet export requirements, mainly to the USA. Do you know what the situation is locally? If you're interested, of course!