Mardee,
Historically many Cal Mac ferries went on to 2nd lives in other countries, notably Greece but other places too around the world (and some went on to other Scottish or Irish operators). The same applies to many cross channel ferries (England to Europe) which go on to operators across the Med.
Off hand I can't remember which it was, but one was converted to a luxury cruise ship which became the late Queen's Royal Yacht (under charter) in Scotland after the HMY Britannia was retired.
Auchterless will remember The Pioneer. She ended up in Sao Tome and Principe (West Africa) 20 years after retiring from CalMac.
From the Isle of Man there is a long history of their retired ferries ending up in the Azores for some reason.
In this case the breakers yard was the only option. She had to be retired now as she has essentially lost her SOLAS certification under new rules. For a ship of her age and design the adaptations required to gain a new certificate would simply cost too much. It doesn't mean she wasn't safe just that she didn't meet new more stringent requirements.
The same as the brand new ferry for the Isle of Man (the Manxman) apparently can't sail to Dublin (a Steam Packet seasonal port) because she doesn't meet EU requirements regarding her rescue apparatus. This isn't SOLAS seemingly, but supplementary EU rules.