Seeing all these depressing threads about bad nurseries I just thought I'd share our experiences of our one where ds went from just under6 months to 3 1/2. It is Beginnings in marble arch www.beginnings.org.uk. If you search through my posts from 3 years ago you'll see that I like many others was not sure about the whole nursery idea particularly for a child that young. Thankfully they've been brilliant and it has turned out wonderfully.
From the fact that they were happy for us to turn up unannounced and sit in for 2 hours and then gave us a month free settling in in which I stayed with ds until I was comfortable leaving him. I then stayed in the staff room and then the local area in a gradual (more for my benefit I think) process of settling in. None of the staff seemed to have any problems with a parent in the baby room for a whole day and it really gave an opportunity to observe.
The turnover of staff has been low and whenever new ones have joined they've tended to have been temps who have already been tried and approved over a longer period.
There is an onsite cook who is very caring and plays with the kids too (the administrator and cook are both CRB checked and the kids interact with them as well as the usual staff in the rooms). There is also a roof garden for outdoor play. They do whole nursery trips to hyde park and the older ones go to soft play in the leisure centre down the road occasionally.
I always felt that they took any concerns I had seriously and would make time to discuss anything I wanted and made helpful suggestions on behavioural and development issues as we went along.
So if you work or live near Marble Arch I cannot recommend this nursery enough.