Freshers week for 2014 was the last week of September, 28th if I remember correctly.
Could be wrong about this but depending on your course you may have different times off from others in your reading weeks.
It also will be different for most people at the end of the year too depending on the course and if you have any exams etc. I finished before everyone and had no exams so was able to leave ahead of most.
For Christmas last year I remember it being a late finish, the 22nd of December possibly, and then about 4 weeks off.