Wherever you do your pre-CPL hour building, remember to do it THE HARD WAY, i.e. do the VFR navs sticking to the CPL margins, with VFR dead-reckoning, a proper log, some general handling, practicing glide approaches, PFLs (remembering the 500 ft rule), flapless approaches, some radio-nav fixes during the VFR legs, etc. These are all part of the CPL skills test, and practicing beforehand will give you a decent head start.
I had about 25 hours to do while waiting for my ATPL results and before starting CPL, so I went back to France, signed up with a local flying club, got checked out and did quite a few VFR navs there.
A good idea also is to try to do your hour building in a similar a/c to the one you'll be using on the non-complex part of the CPL course - for instance a PA-28 if you'll be using a Warrior, so you'll have a seamless transition.
Enjoy the CPL
