Hi there - just saw your message and not sure if you have decided to try swim academy or not but wanted to say I have done it with my ds - started when he was 11 weeks - and it is fabulous. He is now nearly 2 and we are still going he loves it.
I know loads of people who've done it and they've all loved it. It was too expensive for me though and there was a long waiting list this time last year.
We went to the Monday sessions at Carn Brea instead which are less about teaching them to swim but more about getting them acclimatised really. It's nowhere near as good but it's only £2 a session. I bought this so that I could do the teaching myself!