Hi. Did the CPL fixed wing in th '80s and then went back again to do the ATPL about 18 months later. Times have probably changed, but back then it was really frustrating having to go over a load of the same stuff again with a few add ons for the ATPL.
My advice, do the ATPL theory rather than the CPL. Not a lot more content and you'll be more marketable if your aspirations change.