Locally (also West London) there has been a fair bit of chat this year
about badly maintained Thames Flooding systems.

Apparently there are loads of surface water drains that empty into the
Thames that should be sealed off with flap valves that prevent the
high tides backing up into the drainage systems.

However, these don't work when they are clogged up with wire /
branches etc. etc.

And no regular maintenance system seems to be in place.........