i take it you've been to the UKBA website ?

http://www.ukba.homeoffice.gov.uk/vi...rs/settlement/

To qualify for settlement in the UK as a domestic worker, you must:

have been living here legally for the last 5 years;
currently have permission to stay here as a domestic worker;
have been in the UK as a full-time domestic worker throughout the 5 years;
have maintained and accommodated yourself and any dependants without the use of public funds throughout the 5 years; and
have sufficient knowledge of language and life in the UK.

To apply for settlement, you must use application form SET(O).

have you taken the 'life in uk' test yet ?

also

Evidence of employment

You should provide recent documents from your employer confirming that you are still needed and that your employment within them is continuing.