332M, I think you will find that no matter what type of aircraft you fly commercially in the north sea, you do not need an atpl
But you're highly unlikely to get a job on the North Sea without an IR!
In addition, some job adverts recently have specified JAA ATPL as a licence (which would include an IR) but only doing VFR work! An experienced CPL should also be capable of the thing but may not get a look in!
Cheers
Whirls