IR groundschool before ATPL?

[NotAnotherUsername]

I'm considering doing an US/Oz/Canadian/whatever SE IR and then converting it onto my UK JAA PPL licence by doing the JAA IR groundschool plus 15 hours training.

What impact would this have on the ATPL exams? Would my 8 passes for the IR mean that I wouldn't have to sit those subjects for the ATPL or are they different exams and therefore have no bearing on the ATPL exams?

Thanks