The Puma can and does winch but is not equipped for salt water ops in the way that the Wessex was. In Belize it was a standard fit and also I believe in the Balkans.
SAR coverage of the NI coastline is nominally provided by an RN Sea King from Prestwick. International SAR co-operation is to be encouraged and I believe it not unknown for a Norwegian S61 to attend a `downwind` job near Scotland to then continue onto Scotland to a hospital.
I would be interested to know if the IAC cab was local(ish) anyway or called from way on south, (Not that it makes any difference). Of course the navy SAR boys could have been medal hunting elsewhere.