The gap you are describing is the most damaging thing a workplace can have. Not a leader who is openly difficult -  we have all worked with that person and at least everyone knows where they stand! A leader who says the right words and does the opposite is the hard one. That teaches people the values are decoration, and that the real rules are unwritten.

You need to be deliberate about how you raise it so it lands effectively:

Do not open with the values or the training. A senior leader who talks over people rarely thinks they are the problem, and quoting the wellbeing strategy will not work. Let us be honest, they probably do not care about it. Open with behaviour and effect. In that meeting on Tuesday, three people stopped contributing after they were cut off. Here is what I saw. Here is what it cost us. Specific, observed, recent. Not a character assessment.

Bring evidence they cannot dismiss as your opinion. Most HR people forget to bring the proof and just talk about culture. Show recent engagement scores by team. Show who is speaking in meetings and who has gone quiet. Walk them through turnover in that leader’s area against the rest of the business. If the people leaving that department all say a version of the same thing, that is not you having a view. That is a pattern with a cost attached, and senior people respond to costs.

And there is a hard-nosed cost you can put in front of them if you need to. A leader who behaves like this can walk the business straight into a constructive dismissal claim. In the Republic, the Supreme Court in Berber v Dunnes Stores confirmed that every contract carries an implied duty of mutual trust and confidence, and what counts is the impact on the employee, not what the leader meant by it. In the North, the same principle comes from Malik v BCCI. So culture is not the soft issue people think it is. When someone resigns and points at that behaviour, it tends to get attention in a way a wellbeing survey never does.

Don't just highlight the problem - come with the solution. Late night emails are a good example because the fix is easy and visible. Ask them to use schedule send. And if you are in the Republic, talk about the WRC Code of Practice on the Right to Disconnect has been in place since 2021,  while breaching it is not an offence on its own, the WRC will weigh it up in any related complaint. In the North, there is no equivalent code yet, so there it is simply good practice, but the point still lands. Ask them to be the one who invites the quietest person in the room to speak. Small, concrete, repeatable actions change what people see far faster than another all-hands about respect.

Be honest about your own position too. If you are junior to this person, you may not be able to fix this alone, you may need to escalate your concerns. Your job may be to arm the person who can act with the evidence, rather than to have the confrontation yourself.

It is hard, but sometimes we have to accept the limit of the role. HR can name the gap, measure it, and make the cost impossible to ignore. HR cannot make a leader want to change or force them to care about values. If you have laid it out plainly, with evidence, more than once, and nothing moves, the problem is no longer that the message was not delivered. It is that the organisation has decided to live with it. That is a different conversation, and an honest one to have with yourself about whether this is a place you want to stay.