Sandy
To be fair, the initial radio fit/buy was delivered in the mid-80s, although the specified SIMOPS (which drives all comms designs) was unnecessarily complex brought about by the endorsed dual role (ASW and HC). The role mod to convert from Primary (ASW) to Secondary (HC) roles involved removing 2 Station Boxes and 2 Secure Amps, and adding a CDA and BID unit. The Merlin airframe lagged and by the time it entered service this dual role had been abandoned but it still needed an immediate avionic MLU. The comms sub-system was well over 15 years old at ISD, but by no means the oldest.
(Sea King HAS Mk6 comms was in many ways an upgrade to Merlin although some cheap and nasty elements were retained which negated much of the money spent. ASaC Mk7 was a further and far more substantial upgrade, getting rid of these nasties, but which was also degraded when the programme was moved to Yeovilton in 2001 just as the MAR/RTS was being prepared. The build standard that was successfully trialled in 2000 was changed to a pre-1996 and unsafe standard, an act approved by non-technical staff who were permitted to overrule the correct, certified design. This contributed to the 2003 mid-air, as it degraded situational awareness).