Not only is there Dragon and paco's course (which does look quite good!), there is also Atlantic Flight Training in Conventry who offer CPL(H) ground school; it is however, more fixed wing based!!
As far as I know, all the CPL exams have to be taken at Gatwick and they are only run every two months, instead of monthly like ATPL. When I sat mine, there were people who came down from Scotland so I don't believe there's an alternative (unless this has changed in the last couple of months).
CPL/ATPL debate? Clue - I did CPL. Wish I hadn't now; should've done ATPL.
The saving is four exams (9 CPL; 13 ATPL). ATPL for example has Gen Nav and Radio Nav as two separate subjects. If, say, you were weak at one of those, you could pass the other whereas for CPL, the two are lumped together so any weakness in one area could let you down.
Secondly, the syllabus is not that much shorter than ATPL so one has to learn almost as much stuff but over fewer exams.
Cheers
Whirls
Paco, you forgot E&OE!!!