Here's how I worded mine:
Qualified and experienced nanny available for part-time, permanent work from August 17th 2009.
Though I have worked solely with babies over the last few years, I have experience with children up to the age of 13.
I have great references, an enhanced CRB disclosure, paediatric first aid certificate, full clean driving licence and my own car.
I am also available for ad hoc babysitting and occasional overnight care.
I cover the TS postcode area, plus Northallerton, Thirsk, Sedgefield, Wynyard, Whitby etc.
Contact me for further details.