I agree that the bus lane has signs permitting cyclists however the bus lane finishes at 48 seconds in where the left turn arrow on the road just before the lights and is has painted "Except buses and taxis"
Personally I would have stuck in the same lane and done as you did (apart from the close pass of the brompton) but I wonder what the regulation is there
Personally I would have stuck in the same lane and done as you did (apart from the close pass of the brompton) but I wonder what the regulation is there