Hi,
We used Brenda Hart:
http://brendathenanny.co.uk/index.html when our twins were just 5-6 months old and she was great. She definitely works with older children too.
She is a no-nonsense, straight-talking northerner (I mean that positively - my partner's from Yorkshire!), so be prepared for that, as she will tell it how it is, but I'm pretty sure she could help you out.
Good luck!
Jules x