We don't any more toy-town street circuits. We have Singapore, Valencia and Yas Marina for that.
A second race in Britain is highly unlikely given the drive to expand into India, Russia, USA etc etc. These are already at the expense of European races.
A circuit which passes through Admiralty Arch? They may have done something like that at Donington Park in the 1930's but I think there might [absolutely rightly] be just one or two safety concerns about it now.
Leave it on the simulator where somebody's PR department meant it to stay.......