There is no ban or restriction Captainmac -just, the JAA haven't actually got around to writing the CPL exams yet. They wrote the ATPLs first, and then changed the system with the exams only half written. It should have been done by now but they made such a god awful shambles of introducing the JAR ATPLs at the start of the year that they haven't caught up with themselves yet.
Hence the reason why I believe it's not possible to do CPL theory at the moment - I believe 4 forces were working on approval to teach the CPL theory syllabus but they obviously aren't any more. Doing the ATPLs isn't that much harder apparently anyway, there is only supposed to be something like 15 or 20% extra study for the ATPLs instead of the CPLs, a bit of high speed flight and some more tricky global meteorology etc.
At least that's my understanding of the situation, anyone else know different?