Geoff and others.
Regardless of the road system planning problems created by the partially sighted designers, Castle Street is quite rightly closed off due to the sheer numbers of people trying to cross on one or two crossings which is patently dangerous on such a fast road with heavy traffic. The daftest part was not rerouting traffic properly, but hey, we've all been down that 'detour' that peters out into a dead end or sends you 50 miles out of your way.