When did she give you written notice of her holiday dates for August?
Contract says: The registered childminder agrees to: "1)e) Give at least 4 weeks written notice of annual holiday and as much notice of other leave as possible."
It later says "The registered childminder and the parent(s)/guardian(s) agree to consult and review this contract every 6 months." There is then space on the contract to write the dates of the reviews. Last review was on 26/09/13. So there should have been one 6 months later - end of March 2014. Was there?
Holiday year looks like it is incorrectly filled out (they included the year). Will assume that they meant to put 1 Jan to 31 Dec.
Charges: Childminder paid time off 4 weeks £18 per day (note 18)
Parent/Guardian paid time off 4 weeks £18 per day (note 19)
So what is both were off at the same time? Is it whomever notifies (in writing) first, that starts the counter for their particular 4 weeks? Can the other party then still take their full 4 weeks at the negotiated fee?
Note18 - Period of time off in the year, which negotiated fee applies.
Note19 - annual holiday each year during which time childminding service will not be required, fee negotiated as a retainer to ensure that the place remains available.
Note21 (this is referred to by Note18 & Note19) - Mentions notice period to give for holiday and says "Unused holiday will not be carried over into the next holiday period unless agreed by the parties in writing."
I can not see where it says that the childminder is entitled to 4 weeks paid holiday in the holiday year in a situation where the contract has ended.
What happens if notice was given on 1st January? Would 4 weeks of holiday been due then? Even though the contract would have ended 4 weeks later so the holiday year would only have been 4 weeks long.
The childminder is entitled to take 4 weeks off and be paid £18 per day for that time off. However I can not see where it says that they are due that amount if they take that time off (even if they have notified about it in writing already) at a point following the end date of the contract.
By giving notice now, the end date of the contract is BEFORE their holiday, so I do not feel you owe they any money for their time off.
Offering that they keep the deposit as a goodwill gesture I feel is fine to do if you feel you wish to do so. It may be enough to persuade them not to pursue legal action. If they do want to take legal action, then let them. See if they can convince small claims court that you owe them money.