I think TTTE has summed up the situation.
"Re-passing" in THIS CASE may be associated with having taken the old syllabus rather than the JAR Interim H (or the 'new' JAR sylabus whenever somebody finishes it ...)
However the Interim H is based on the old national sylabus plus some (well, quite a few actually) JAR A papers.
So how different is the content? Perhaps there will be a conversion course to cover areas not addressed in the nationals for CPL(H) - oneday
If, having taken a CPL(H), and then an IR(H), and having accumulated night, multi pilot, etc hours to ATPL(H) standard, a UK based pilot was then refused a ATPL(H) there may well be 'hell to pay' because most people go that way because of the time and cost issues.
Especially as "grandfather rights" leave people today with a ATPL(H) designation which is essentially a CPL(H) but from pre JAR .....
Hardly a level playing field by any stretch of the immagination.
Discriminatory? Perhaps