Sheepgirl, I would not sign up to this contract. If I go on hols or my child is sick or we don't show up for whatever reason when the childminder is available, then fair enough I'l pay her in full without complaint.
But, no way no how do I pay someone who is not en emplayee to go on holiday.
I would ask her:
If she goes on holiday or is otherwise unable to care for my child, does she have a back up of someone else who can cover for her for the same price (and not pay childminder who is away)? When I used a childminder, she would arrange for another childminder to look after my DD when she was away. She would give me tons of notice, she would get other childminders paperwork, and would offer for me to meet other childminder in advance if I wanted.
£5/hour is steep in my opinion but may very well be market standard. In Twickenham the going rate is £6/hour (per child!). I do know people who pay for childminder's hols, but again, I would certainly not sign up to this.
How much notice is she going to give you for when her holidays are? I have a friend who is rather miffed at the amount of holiday her childminder takes (and she then has to pay half plu find other childcare). Crazy.