Swimming

Hi All,
New to the community so I hope this is right.Our 3 year old son who has CP started swimming lessons last October, he loved it but in the last few weeks they haven't been going as well.We are worried that we may have started lessons too young although we want him to swim every week and the small class was supporting him following group instructions.
We just wondered what other parents had tried? Parent and toddler lessons?one to one lessons or taking them frequently?
Also any ideas of organisations who may also be able to give us some advice?
Many thanks