Domestic helper - housekeeper and childcare

We are a British family (both parents work full-time) with two boys (aged 8 and 4) living in Sai kung.  Both the children will be in school from August so the main duties will be housekeeping and babysitting as required, also cooking and preparing packed lunches and snacks.  We also have a dog who is getting old but enjoys a daily walk, there are plenty of places to do this on the doorstep.
We are looking for someone with initiative and the ability to work independently.  We welcome a candidate who is energetic and enjoys the countryside.  We are seeking an experienced candidate, with good references and are prepared to negotiate salary and working conditions to reflect this.