I mean, if the Tavistock wants to transition(!) into being a "gender affirmation service", then sure, having people who believe in "affirming gender" in charge makes sense.
But they can't have it both ways. If they're a "gender affirmation service", then it's not medicine, and the NHS should withdraw funding.
If they want NHS funding, then being able to work within the evidence is a prerequisite - and previous behaviour and investigations and lawsuits show that they have a current leadership incapable of doing that. They're closing their eyes and ears to anything that upsets their "customers".
So they need GC people on the board (or at the very least people prepared to listen to GC voices) to restore balance, and ask the difficult questions that need to be asked. It's in their own best interests to do that now, before the malpractice scandal gets any worse.
A Tavistock with Baroness Nicholson on the board asking questions would be a hell of a lot stronger.