Would it be wrong to stop a convicted pedophile who has spent his sentence from babysitting my daughter?

I have been advertising for a babysitter to look after my daughter while I work. The best applicant was a 46 year old I accepted his application. However we did all the checks on him and found that he was a convicted offender, but spent his sentence more than 7 years ago and received counseling, etc and had remorse for his crimes. I am very wary about giving him the job but the police and my lawyer have told me that I would be in a legal quagmire if I was to fire him as his sentence was spent. It means I would have to fire him and it would lead to unfair dismissal etc so I have to let him look after my daughter now. I have purchased a voice activated recorder and will leave it running throughout his visits to my house to make sure everything is above board. Is there any other tips I can take to magnify security?