Looking at the new times it seems passengers travelling from Haywards Heath may have an even longer wait at Gatick Airport, than they do now, if connecting with a North Downs Line service (Gatwick Airport to Reading). I had hoped it would be faster, like it use to be before thwy started the Thameslink works.
The only caveat is that it maybe that those North Downs Line services are not fully in open train times yet or are to be revised further.
Currently the wait is officially 24 minutes, although one can get a 9 minute unofficial connection.
Going forward the wait will be 28 minutes and the unofficial connexion drops to being 4 minutes. Given it's Southern I wouldn't want to ruy on an unofficial 4 minute connection to an hourly service.
For reference I looked at the potentially new 12:30 Gatwick Airport to Reading service and the current 13:03 Gatwick Airport to Reading service. I then checked for the connecting trains tonhose services.