James is a busy man, he has a full time job and a young family.
He will be working with council's, the FA, other leagues and clubs on this weeks fixtures - this is no easy task, each and every week
He will also have lots of messages from clubs all the time about this week, next week, the week after etc etc etc
He will get back to you.
I would suggest an email to confirm your request and he will get back to you in time. You have given plenty of warning so assuming there are no other details that I am not aware of (County Cup/already used your free week) I would expect your request to be granted.
But given that the fixtures for the first week of Jan have yet to be confirmed I suspect the last week in Jan is not top of his priority list.