Just a heads up, as I've not seen it covered anywhere (but Mods please merge if there is an existing thread), that as per the TFL weekend travel update this weekend (Sat 16th and Sun 17th Nov) there will be the following train closures:

No service between Paddington and Heathrow
ELIZABETH LINE: Saturday 16 and Sunday 17 November, no service between Hayes & Harlington and Heathrow (All Terminals). Please use Piccadilly line trains between Central London and Heathrow or London Buses for local connections.
The HEATHROW EXPRESS will not operate on this weekend, including between terminals.

No Southern Railway or Gatwick Express services to or from Victoria. This is due to Network rail engineering work.
Please use alternative rail services from London Bridge, including for journeys to Gatwick Airport.
Southern Railway tickets will be accepted on the Tube between Victoria and London Bridge.