I expect with the winter schedule TUI, and maybe EasyJet, will be operating once again solely from the North Terminal. However they may use both again South in summer 2023. The TUI flights from South this summer have all been operated by aircraft leased in and operated by the likes of Titan and Smartlynx. Titan tend to fly from South when operating from Gatwick be it for themselves or others.
BA leased easyjet quite a number of slots this summer. They may be taking some of those back if they continue to expand their long haul and short haul flights next summer. This may mean fewer EasyJet flights from South in any case.
I personally can’t see Norse operating anywhere near 8 787s from Gatwick next year.
Don’t forget pre-Covid BA we’re operating 15 777s and up to 32 A320 Airbus aircraft from South during Summer 2019. I don’t think the capacity of the terminal is an issue for a while yet.