If you're starting on Basic in January, your first period of leave will be between basic and your rating course.. so probably at the start of April for a period of approximately 10 days.
However, don't plan or book anything based around what you hear your holiday times are.. the last basic course was extended by 1 week with only a month's notice, and the holiday was not increased to compensate for those who then went on to aerodrome.. This somewhat screwed up at least 2 people's holiday plans which had to be cancelled.
They do warn you that holiday times are not to be taken as gospel and things do change but you must treat whatever you're told with a large pinch of salt!
(Lastminute.com is your friend)