I think that's mischaracterising why people might be leaving now. If you were simply appalled at the financial management you'd have gone a while ago. If you're leaving now it's because of the response.
Exactly this. I'm godsmacked you need it spelling out.
Scenario 2. The 2022 finances are actually quite well understood. They had to be in order to file an accurate Corporation Tax return. HMRC aren't big on allowing such things to be wrong based on the argument that, "it's all too much effort". If there's any likelihood that the BMC didn't understand their finances correctly for 2022 and may have filed an incorrect Corporation Tax return then it is probably rather important that this gets investigated urgently just in case they turn out to have a massive tax liability. So assume the 2022 finances are well understood, but they're embarassing and not just to people who have left the organisation. People within the BMC are desparate not to have all this uncovered and are really hoping that it all gets forgotten about.