JJ
but it doesn't specifically say that the pilot needs to resit the IR test papers
Yes it does:
FCL.625 IR — Validity, revalidation and renewal
(a) Validity. An IR shall be valid for 1 year.
(d) If the IR has not been revalidated or renewed within the preceding 7 years, the holder will be required to pass again the IR theoretical knowledge examination and skill test.
IRE as per
FCL.1005.IRE IRE — Privileges
The privileges of the holder of an IRE certificate are to conduct skill tests for the issue, and proficiency checks for the revalidation or renewal of EIRs or IRs.
The IRRE can only do revalidations and renewals.
IFR comms was not part of the ATPL but the FRTOL
IFR Comms was introduced by the JAA in 1999 and relates to the ATPL and IR Exams. It has never been associated with the FRTOL which had its own TK exam pre -JAA and has used either the JAA/EASA VFR Comms exam, or the UK PPL Coms Exam since 1999.