Looking For Establishing A Babysitter For Ad Hoc Days When I Am Travelling For Work

I am looking for establishing a babysitter or a few for ad hoc days when I am travelling for work, now and then I have to commute to London from Plymouth, and, while I have full time nursery arranged, sometimes if Julianna is ill and cannot go to nursery, I am going to have to arrange someone coming to our house (in Barbican) and stay with her.