The first half from Hampstead to the Serpentine is by far the most stunning, so you could just stop at the Serpentine and have a lovely breakfast. After a 4.5 mile run and three cold swims you’ll have earned it.
Make like the Brownlee boys
Turn the Swimmer into a triathlon – transition to a Boris bike at the Serpentine car park and cycle to the docking station at Chelsea Bridge. That knocks 2 miles off the final run (or you could then jump on a train at Battersea Park to Balham).
Let the train take the strain
Hop on a Boris bike at the Serpentine and cycle to Victoria. Catch a train to Balham or Herne Hill for the final swim.
Bust a move
After the Serpentine, jog down to Sloane Square and get the 319 bus to right outside Tooting Bec Lido.
If you can think of any more shortcuts, let us know. The most inventive gets double portions of millionaire’s shortbread.