Flexible childminder for 1 baby boy

We are looking for a childminder starting in January to look after our little boy who will be 11 months. I am a nurse working 3 long days a week and my partner is in the Naval service. We are looking for someone flexible ( 3 days required 1 week, 1 day required the next) this may change when my partner will be going to sea or according to off duty. Notice of working days should be 3/4 weeks in advance. Our little boy has cow milk protein intolerance so currently on a dairy free diet.