If your child doesn't have a disability they are not eligible for disability lessons. You may wish to speak to their swimming teacher to discuss any issues.
If your child does have a disability then you should first speak to their swimming teacher for their opinion on your child's progress. We always aim to keep children in mainstream lessons where possible, however if this isn't suitable disability lessons are the best option. You will need to complete the Swimming Lesson Adaption Form (linked above on this page).