My 3 and 5 year olds do weekly swimming lessons at Norwood Swim School. It's hard to rate them - some teachers are great, others not; some admin staff are great, others not; consistency is definitely not a strength. My 5 year old has been going since he was 6 months and received only 1 certificate (when he changed from dolphin to pufferfish class), my 3 year old received 2 certificates in her class last week alone! Teachers do not appear to keep even brief records and very few provide feedback to parents unless asked. If you miss a class, it can be difficult to arrange a make up class, particularly to book ahead, it seems to be more of a last minute possibility. If they introduced a cancellation policy - 12 hours notice or no make up class (ie people would lose out financially) I think they would have a better idea of which classes are not going to be full further in advance and therefore could offer more options.