Crystal palace pool is quite nice, but the changing room and general environment are grotty. Go to Peckham, don't be snobby. It's lovely. Greenwich the Arches is nice but hard to park. Deptford is nice too. The Spa at Beckenham has a nice soft play too, as does Peckham. It's quite pricey, the Spa. ?7.10 to swim, mum and child.