Suggest you do some research before posting next time.
CAA website on the home page a link to closing dates.
CAA Winter Break
But to summarise - closing Mon 26th Dec till Mon 2nd Jan Inclusive.
Suggest you apply for all your exams (If you know when you want to sit them) this year as they're £55 and next year they're £60 from 1st Jan. All prices are at application so if you apply before the 26th you save some money - every little helps.