Get yourself a copy of the CPL sylabus. Use the hour building phase as preparation for the CPL. Force yourself to brush up on your weaknesses. It's the ideal opportunity to make yourself a better pilot and pass your CPL within minimum hours.
You could also take an instructor (ideally one who also knows the JAA CPL sylabus) with you every 8-10 hours and treat that flight as a CPL mock test. When you do the CPL module itself it shouldn't be much more than a refresher of what you know.
If you have the right objectives and plan of attack, I think the hour building phase is far from a waste of time. If self motivaton is a problem, I would advise an Integrated course.
cheers, JT8
