My DD goes to Kidsunlimited on Ladbroke Grove. I am very sad that we will be moving her from there at the end of Feb as we have moved to Battersea. It's the cleanest we found. Newly renovated so nice and bright. Good facilities. Most importantly out door space which is hard to come by in London. It's not cheap (£92.50 a day for DD 21 months) but gets cheaper depending on how many times she goes. All inclusive of nappies and meals. The staff are lovely. Very caring and kind and my daughter has become very close to them.
By the way we looked at a few and they were dire. The Warwick down on Harrow road is a dive. Snotty noses everywhere and very poor facilities. Staff seemed very sparse and toys included a bit of sand in an old coke bottle. There are a few nice ones around nottinghill especially the spanish one and ladbroke square but expect to be gobsmacked! The prices are extortionate and you might not find any availabilities. Oh you could try the beehive montessori off the m queens park but it's from 2+ years and when i called to book a viewing they took a month to return my call...A MONTH!