From what I understand it is not an either/or situation.
AFAIK you need 150hrs TT of which 100hrs must be PIC.
I could be wrong though.
EDIT: By chance my instructor just phoned me, and his interpretation is that you need to have 150hrs TT to start the training, but that you need 100hrs PIC to sit the skills test. But like me he isn't 100% sure as he's never come across anyone with less than 150hrs or 100PIC starting a CPL modular course.
Regards,
Gordon.