In which case who stuffed up and called the rescue service in the UK?

Surely not the person being rescued if indeed he did use a phone then the call would be point to point and hardly able to be received by a random recipient.

Chris6791 said..

Could have been a speed dial mistake or a sat phone?

Even so, still doesn't answer the question on how the UK rescue mob got the call unless it was programmed into the phone's speed dial.
To dial the UK you need to prefix the call with the country code before dialling the number, in this case +44 and then the rest of the number, hardly the sort of thing you can do by mistake or even coincidence.

None of the people in the sinking yacht were identified by name yet the watchman at the UK facility was identified as Arwyn Williams and then it was confirmed that three people had been rescued. Who confirmed it? We have heard nothing from any Australian rescue mob. I don't believe it happened.

Here ya go twas Mr Google
www.mirror.co.uk/news/uk-news/australian-sailors-swansea-sos-call-2945000