Please do not expect your child to make equal and constant progress every lesson. Learning to swim is not the easiest of accomplishments for all children. In particular the breathing technique can be especially difficult and may take several lessons before the pupil can master it.
It is common for children to appear to make no progress at all at some stage, in fact they may even regress for several lessons. Please be patient, it will not be for want of trying by the Teachers and they understand it is part of the learning process. Parents should try not to convey anxiety over this to the pupil. We teach them all to swim! Some make rapid progress, some take longer!