LASORS J1.7 does not suggest that issue of an FAA IR(A) 'secures' the ATPL exams.
JAR-FCL 1.005(a)(2) states "Whenever licences, ratings, authorisations, approvals or certificates are mentioned in JAR–FCL, these are meant to be licences, ratings, authorisations, approvals or certificates issued in accordance with JAR–FCL. In all other cases these documents are specified as e.g. ICAO or national licences."
LASORS J1.7 is a direct copy of JAR-FCL 1.495 and, since no specific mention is made of ICAO or any National Authority, IR(A) means JAA IR(A). The idea that the issue of a foreign IR could 'secure' the JAA TK exams is ludicrous.