Complete and utter bolox.nonsense - you are interviewed under caution if you are suspected of committing a criminal offence.
All police interviews are conducted “under caution”
Anything not conducted under caution is not an interview.
Anyway the police had already dismissed it, it’s only the fact grifting Conservative MPs put pressure on the police to investigate.
Anybody with a brain can see it’s not a police matter, it’s a tax matter.
What criminal offence has she committed? - the only one I can see is electoral register fraud and the police aren’t interested in anything somtrivial