The CPL course cant really be combined with a family holiday. Trust me on that. You will need to concentrate on the work 100%. The weather will play a significant role in how long you will take to complete the course. Just think that each beer you scoff will cost you £100 due to the lack of brain power/hangover next day.
If you dont have a twin rating yet you will have a ground exam for that, so there will be a bit of studying for that. Any areas that are causing trouble may need a bit of reading in the evenings (usually something to do with VFR nav).
Sorry if I sound negative but that is my experience so far.