I'm sure that there would be childminders offering wraparound care; and also breakfast and afterschool clubs at both BP and Earlsfield. You might find it easier to post on one of the SW18 Mums' Network pages on Facebook, as there are fewer SW18 Mums hanging about on here.
Like the previous poster, I have 2 children at Swaffield (one in nursery and one in year 3), and am very happy with the school. It is large, friendly, and diverse. I have used both the wraparound care on offer at the school; and a local childminder - my children have enjoyed both. There are so many extracurricular activities, and opportunities for the children to try a new skill. My eldest has benefitted from choir, ballet, recorder, chess club, fencing, tennis, Playball and Bollywood dancing lessons, during their four years at Swaffield, to name but a few of the clubs!
Feel free to private message me with any questions.