Thanks for all the responses people, much appreciated.
Because I'm keen to become an FI as a career, if only part-time, then I'm going to need my CPL. Like Whirls said, why not use the time I'll be building to put towards the CPL? My aim is to fly as a career, not a hobby.
One other thing: if I decide to do my CPL ground exams instead of the ATPL exams (which is likely), am I able to do the additional exams to convert the CPL to ATPL?
Tim