DD is 10 and in Y5 and she's very happy going to science camp/theatre camp/sports camp this year. They all go up to age 12 and I think she'll still enjoy the theatre camp next year but she was the oldest at the sports camp and among the oldest at science camp.
However DS has SEN and while he is also being kept busy (1:1 swimming lessons for 2 weeks) DD will not want to be at home with him and DH for weeks on end in the future.
I imagine she'll meet up with school friends in town or at their houses and appreciate a few days to chill but if anyone has any good ideas for us to investigate... she might well like something a bit more mature in October half term as well.
She can go to PGL, I know, and we'll definitely look at that, and she's joining Scouts but their camps tend to be over a weekend to accommodate leaders who work. All the "learn a sport" camps are for much younger children, and her own favourite sport is cycling, but she's not old enough to go off for a day's bike ride (nor will she be aged 12), and they don't run extra daytime clubs/classes for her age group in the summer. She isn't musical, doesn't dance, and the theatre clubs all run at the same time (in term time) as her cycling club so she can't progress much in those beyond a week in the summer.