Assuming you have a valid ATPL(H) with valid IR you'd need to do the following:
A. Do 5 exams (PoF, instrumentation, AGK, Perf and Op Procedures)
B. Get a PPL(A) and hours build to 100 hrs PIC (also grab a night rating in there - 5 hrs)
C. Get an MEP (5 hrs), ME IR (10 hrs because of heli IR), and CPL (15 hrs)
D. You'll have MCC credit so then it depends on the job offered.
Couldnīt you then do a PPL(A) in the US or Canada (where it is less expensive to fly), fly the 100hrs, then come back to Europe, do a PPL followed by a CPL?