....a textbook CDA approach from the hold with the throttles almost closed right down to 600'....
In BA that would not have been a 'textbook CDA'. It has been covered numerous times before ad nauseum.
Core icing is a known issue in certain defined conditions on the ground with Trent B777 engines and we have procedures to follow when it is a possibility.
In the air we have no knowledge or requirement for any procedures relating to core icing. As has been mentioned, it has now been discovered that it is possible in certain conditions but we have received no official communication on the subject.