Spoke at length to a dealer at the Scottish Show where Yamaha had a Niken on show , apparently only a small number of dealers in the UK will be selling them (same as the electric EC03 moped ) and he doubted that any would stock demonstrator bikes unless they were supplied by Yamaha UK.
His main concern was who if anyone would actually put their money down and buy the bike , Yamaha have been bitten in the arse in the past by introducing 'different' designs of bikes they though people wanted and needed to find that no-one actually bought them ie TR1, GTS, XV550 plus others.
My thought was fine if it is like the 3 wheel Piaggio and legal to ride on a car licence , however, as he pointed out it requires a full bike licence and it may well be a major stumbling block with the fairly conservative bike buying public.
Think it may well up being a development dead end