Incidentally, I was just looking for a somewhere to pull over so I could look on google for an alternative route as sat nav was sending me down the Rotherhithe Tunnel and my van is too high for that, so I pulled in to Neptune street. I can't say I noticed any 'no right turn signs' they must be quite far before the turn- I could have missed them but when I have to drive through London I am always on high alert for this kind of thing.