TfL have a press release about changes to how buses will run from next week, aimed at helping the service operate in the new school term:
There is a full list of route numbers at the bottom of the press release, giving those that will have the special School Services and those that just have extra buses. The 356 is listed as a lower frequency route that will have extra buses around school opening and closing times. The 75 is not listed.
176, 185, 197, 363 and P4 all on the list that have school services but no extra buses from what I can see. I’m assuming that means that every other bus won’t be available for adults. Might be worth allowing extra time if you have to travel at peak times.
The 122 is also shown on the list of routes with extra buses. I find it strange that the 75 isn’t mentioned at all as it serves Forest Hill School and even pre-covid buses were often full around school finishing time in the afternoon so with restricted numbers allowed that will be fun!