Not surprised if UK authorities were involved to tell them they aren't going. As stated earlier, DHS employees working its Immigration Advisory Program and/or its Joint Security Program have local official complicity when it comes to DHS' ability to operate in the UK and elsewhere. And this dynamic can play itself out in different ways.
It's Norwegian that is the carrier which is refusing to refund the father, his nine children and their paternal uncle their money on a trip to see relatives in California and do the Disney/Universal Studios tourist thing people do in Southern California.