Very paranoid mum here, I have a list which I have prepared and leave for anyone who has my two dss.
It contains;
OUr name and address, Sounds stupid but if had to call an ambulance would want right address given.
Both ds's full names and dates of birth ( see above)
Any medication they are on, and when they last had it
My and dh mobile numbers
Another contact number ie other neighbour who know the boys and my mum in Edinburgh (we are in Watford), it makes me feel better
Normal routines,eg if ds2 wakes give him a drink , if ds1 ventures out of room tell him to go back.
I know all this sounds over the top, but it makes me feel secure and I know if anything goes wrong the babysitter has all the info to hand, and is not relying on remembering things