apologies, some further diligence in actually reading the timetable consultation document has lead me to this:

Current trains between London Bridge and Caterham via Sydenham (Sydenham
route) will continue to operate but after Norwood Junction will instead operate to and
from West Croydon. Passengers for East Croydon or beyond will need to change at
Norwood Junction for connecting trains. From our passenger analysis this will affect
approximately 1630 passengers per day who will be required to change at Norwood
Junction for trains to East Croydon and beyond.

I think the relevant questions for this are no.s 59 and 60 in the timetable consultation document (round pages 40 on) and see also Route SN3.8 on p50. In summary i think we retain the 2 tph hour on the Victoria - LBG route, and also have 2 tph from LBG to West Croydon. So getting to and from Gatwick will be a slog.