Second vote for beaumont leys, they have a baby pool that's behind the kids slide at the back so it's quiet
I’d say Beaumont Leys pool too It’s usually always warm the baby pool perfect temp And I think they offer baby swim classes there and at new parks swimming pools you will have to double check though I think called splash babies and there’s another baby swim classes brand too
I took my little boy (nearly 4 months) to Beaumont Leys pool, the water was a comfortable enough temperature.