As looneytune says, we are a service provider, not a potential employee.
Also, I have just finished reading the Who Minds? Magazine and there's a resolution (p24) which mentions the fraudulent use of childminder's name, address and registration number.
Personally, I would be very wary of e-mailing such details to an anonymous person, who could be anyone. It is incredibly easy to set up an e-mail account with false info.
Going off in a tangent here, but I remember uploading a CV back in 2001 to a supposingly secure on-line job search company. Around 2005, that company then sold the database onto another company and before I knew it, I was getting spam from all over South America and Africa. I actually ended up having to change e-mail address and ultimately internet providers.
If you feel really tempted to reply to those ads, I would e-mail a link to your website, with a sentence saying that if they are still interested in your childminding SERVICES, to contact you as per instructions on the website.