Those details are not require when registering an old bike in the UK so very unlikely to be on any UK issued V5.
Max permissible mass is not a required detail when registering any bike in the UK.
Revenue weight is not require when registering any vehicle 3500kg or less in UK.
Max net power, width, mass in service would be taken from a "certificate of conformity" which dont exist for old bikes, though BSA published annual "data books" which included the engine power in BHP, the width and dry weight.