Agreeing with Incandescent above, there' also a white BUS STOP sign next to the road. However, there must be a yellow sign facing the roadway that says no stopping except buses. Almost every bus stop in London is now a stop for buses only, 24/7/365 a year.
Go and have a look for the yellow sign, if it's missing there's a good chance of winning at tribunal, I speak from personal experience. In my case the sign was there but the council's evidence pack didn't have a photo of it. But I also had a very good reason to stop where I did.