I suggest you ask the family to talk to this lawyer,

John Bautista,
The Filipino Agency,
79 Buckingham Palace Road,
Victoria,
London SW1W 0QJ, Tel: 020 7976 6700.

Like eljean said we don't know much about nanny visas. There are plenty of filipina nannies in west london and I am pretty certain this one specialises in nannies & domestic staff.
Leave it too the family & the lawyer, there is very little you can do yourself