Payment references in friend's bank account

[OliveTheDog]

My friend's exH is the BIGGEST BIGGEST wanker one could ever meet. Seriously horrible and controlling. Her DC has SEN and, by court order, was forced to have contact/stay with the ex. I won't list the many terrible things DC has been put through by him because it would take too long. The DC hasn't seen the Dad for two years now - they reached breaking point mentally and probably physically.
The Dad has now told everyone (eg. school) that he no longer wants any part in DC's life and he is not ever to be contacted
Anyway, my friend mentioned to me today that, over the years, when the Ex makes his CMS payment he has used low level insults as the reference. He recently changed the reference to "Lazy Cunt". However, the most recent reference is "I hope you both die"
Are people allowed to put that as a reference? Can my friend do anything about it although I get she wouldn't want the aggro?
By the way, the ExH is a policeman

I’d I were your friend, I’d find it hard to trust the police. But if she can find contact details for the most senior woman in his force, and email her saying basically what you’ve said on this thread and can she point her in the right direction to getting this sorted through disciplinary, then I think that might work. Most very senior people have highly efficient secretaries who deal with stuff like this, know the organisation well, and will keep pushing if they know it’s something their boss cares about.

Your friend should get a nationwide account as refs don't show up on mobile banking. Just the name

Might help short term