Tandridge in Oxted is our local 'fun' pool, with plenty to keep kids occupied. From slides to water cannon, there's plenty to do, and there also a decent soft play, gym and group exercise set up.
Check the pool timetable to make sure the kind of swim you had in mind is on the cards! They have slots for little ones, serious swimmers, and bigger kids. They even run a "Friday Night Project" session for 11-16 year olds.
For more, visit their site
Getting there: jump on the train from upper Warlingham to Oxted, or hop in the car.