We toured a few and Reflections was, we thought, by far the best and when it's the care of your child you go with that sentiment, not your wallet don't you? (I'm not suggesting you did differently!)
(I've just checked my childcare vouchers account and it was c£450 a month for 2.5 days/week and...
That is unusually cheap if that is the total cost (i.e. you are not netting off 1/2 lots of childcare vouchers etc).
Our last nursery (Reflections, Worthing) was c£500 per month for 2.5 days a week, with extra fees for Forest School etc.