I did my course at Oxford with a few months out in Phoenix. The CEP course is a full-time residential course which usually lasts for just over a year. You are supposed to get a week off during the course, but we never got ours.
Weekends are generally your own, but increasingly you are expected to do some flying during the weekend, usually solo or SPiC work. One or two Saturdays or Sundays a month is usually sufficient, but its all down to you so if you want to do more then you can.
During the week you'll either be on a ground school or a flying day. Ground school lasts from 9 till 5 while a flying day typically involves one or two flights. In the long Summer evenings you can burn off a lot of your hours if you can persuade an instructor to stay on. As exams approach you will find that you get more and more time off, but this is obviously intended for private study.
Hope this helps.