I turned up at Cutty Sark on Saturday to see that no train was
expected for 16 mins. Over the next 5 mins that figure varied up and
down slightly, but not very much.

A train passed heading for Lewisham, so we knew services were being
restored from whatever the problem was, but there was still a mess.
But soon an empty train, horn blaring, passed at speed though Cutty
Sark on what would normally be thought of as wrong road. It quickly
reversed and entered service.

Which is just my way of saying that the traditional UK meanness to
invest in 'frills' like decent bi-directional signalling is
short-sighted. I suspect that the economic cost of failures does not
enter the heads of the money men who fund our railways, as they
probably have been led, or prefer, to believe that if things are
maintained 'properly' such things happen so infrequently that they can
be ignored.