Not much help sorry, I used the Nightnannies agency. The nanny we were sent was excellent and I would have her back in a heartbeat. They do cover this area - Nightnannies SE is the one you want, not the central London branch. The fees are a bit lower. It might be worth trying to negotiate the agency fees (I got 10% off this way) and/or asking what range of fees the nannies themselves charge to bring down the overall cost.