Has 1D been updated recently? Brfares has no generic London Terminals restrictions on return however National Rail and booking engines are enforcing:
London Terminals (except as shown below) Mondays to Thursdays after 06:44 and before 07:59 or after 15:57 and before 17:46 - or Fridays after 06:44 and before 07:59;
London Terminals (except as shown below) Mondays to Thursdays after 06:44 and before 07:59 or after 15:57 and before 17:46 - or Fridays after 06:44 and before 07:59;