I've heard of situations where the panel chooses from among themselves who will chair!
However, I would have thought that, in most authorities, whoever is in overall charge of appeals will appoint the chair (a) on the basis that it's someone who has sufficient experience, and (b) because it's someone whom they trust and can reasonably expect to do the job properly.
For my LEA appeals, Democratic Services department, who run the appeals, allocate the chair. I found for my first year hearing appeals for them (though I had experience for non-LEA appeals) I was a panel member only, not chair, but now I sometimes chair. We tend to rotate round so we all get chance (obviously not during individual hearings). We all have our own style of doing things, but I've never seen a chair who isn't friendly & sympathetic to both sides.
For some of the non-LEA appeals, I turn up on the day and am told by the clerk that I'm chairing, and for others the panel decides before the hearings. In the latter case we do discuss what experience we have, so it is always someone with solid experience of appeals.
Of course, every chair has to start at some point. I remember being probably as nervous as the parents for my first batch as chair - in other words, scared stiff!
Do they have to provide an audit trail?
It's standard practice that a copy of all relevant evidence should be kept on file.
Yep. If a parents has brought evidence that is important, we'd normally adjourn, & the clerk would go off & photocopy it - one copy each for us & LEA & one for the clerk. Our copies are destroyed after the appeal, but the clerks copy is filed with the notes.
This would not apply to school work being handed round - we might flick through it, or adjourn to study it in depth, but really wouldn't need copies of each & every school book presented by the parents. Nor swimming certificates...