I can recommend the teachers at the JAGS pool who are working hard to help my son who is still struggling with water confidence at age 9 (nearly 10). The pool at JAGS is really well looked after too.
We've tried a lot of the group lessons locally and I can recommend Crystal Palace:
We are only going down the 121 route because my son is nearly 10 and still can't swim properly and I don't want it to be an issue for him.
Good luck wherever you choose.