You're right - expensive, and not very good. Ever heard of ATE?? See the other thread about summer camps. Unfortunately, ATE only cater for eight years and up, but might do for your elder one. They collect from various travel points around the country, so you don't have to live near the centres that they use. Have a look at their website - www.ate.org.uk.
good but expensive. we did a group booking so got a good rate but even then fairly expensive. kids did enjoy though - esp good where they have swimmng faclities. also drop off and pick up times are flexible. there are others much cheaper though
I used to take my boy to camp beaumont at Kings in Wimbledon and also Claremont Fan school in Esher - they tend to always a pool but he did get bored after a while - I think it depends on where you go and the group you're in - always best to have a friend in tow - we've now defected to PGL because they have huge discounts if you hang on til last minute - I wonder whether Camp Beaumont do the same - good luck