Having been interviewed by a CAA investigator once, it turned out he was a retired police detective so this maybe is the reason for their attitude,
very confrontational and guilty till found innocent. Not a nice experience even though I was not at fault.
As the CEO of a small flying group for several years have had several calls from the CAA and have found it was a good idea to go through a role play with the operating pilot to get their story straight and have reasons and answers to expected question made a big difference to the outcomes.
As with the police remember they are not your friends and be economical with the truth i.e don't incriminate your self.