If I were the person being called into a such a meeting, I would ,if I suspected an ambush, go in with a recording device operational. There would be no reason to publise that fact and if all the treatment was fair ,it would never see the light of day. I would not volunteer the information that i was recording, but likewise if i was asked the direct question "are you recording " I would answer yes.I would advise caution here, I'm not at all sure what you suggest is legal without at least advising those present of the recording
If push came to shove it is likely it would be inadmissible evidence in tribunal or court
It's complex and not cut n dry. Here is starting point for research
https://www.crunch.co.uk/knowledge/employment/can-i-or-my-employer-audio-record-a-disciplinary-or-grievance-meeting/
If on the other hand the official side tells untruths and puts them in their official memo of the meeting.it would be valuable to have a record. An official side will have more credibility than the individual because it is recognised that the risk and cost to the official side of lieing will be much more than the risk to the individual.