BACS will not be happy
I once reported my mortgage provider to BACS for cocking up my direct debit and writing it to my credit record as a default when it was their fault. What was suspicious was that they started sending the wrong details to the bank just as we had started the remortgage process in place. After a flat refusal to change the credit record, two days after I reported it to BACS they changed it and sent us a letter of apology.
I also did that to the Council when they screwed up my Council Tax (nothing fishy, just incompetence). I was told - through a contact who worked there - that they had to grovel to BACS and agree to being audited by them in order to keep their ability to collect Direct Debits.
So if BACS is working normally, I expect there will be quite a lot of shouting going on right now...