I went to a toddler singing group on a thursday morning
And it was packed with childminders so you could go and check it out. I met a couple of really lovely ones who really took the time to introduce themselves and I could see how they interacted with the children. It's not why I went but it's a good tip.
Or ask at your local preschool whom Tey would recommend of the minders who do drop off/ pickup there. Hurry though because it's the last week of term / groups.