When I was looking for a nanny in this area (SE15) I called some agencies and they said for a "London nanny" ie: some kind of childcare training and Ofsted registered (incs police check & first aid etc) it's ?10-12 per hour which the nanny gets in the hand. We then pay tax on top of that through Nannytax so it actually works at an extra ?3-4 an hour that you're paying in total. Good luck with your search.