As our second appeal is for a Catholic school, can we assume anything about the panel members? I.e. can the school governors pick a Catholic panel?
No, I don't think you can necessarily make any assumptions.
I was surprised at our first appeal that the members only introduced themselves by name, and no mention was made of their qualifications.
I do think it would be good practice for panel members to tell you a little bit about their background, but it's not a requirement.
There are no qualifications as such, but there must be at least one 'lay' member and one 'non-lay'. You can read a bit more about this here:http://www.elevenplusexams.co.uk/appeals/general#a30
How do people get to be chosen, generally?
Often by advertising. The previous Code of Practice stated: "The clerk, acting on behalf of the admission authority must appoint either three or five members to each panel. In any area, it is important to try to ensure a diverse mix of panel members (race, gender, faith if appropriate, etc), but particularly in areas with mixed communities where, as far as is practicable, membership of the panel should be representative of the ethnic profile of the area. This should be taken into account when advertising for new panel members ....
Although desirable, this has never been easy to achieve (because the system depends entirely on volunteers willing to undertake this sort of stressful, unpaid work). and I see that the above statement about a diverse mix is not included in the new, slimmed down Code.
Unsurprisingly, retired folk often make up the majority of panel members, and many of these may well be people with an interest in education (e.g. school governors, retired teachers).
When presenting the parents' case, is it necessary to cover everything in our written submission,
No, I don't think so.
..... or can we safely assume that the panel will have studied our documents in great detail (and remember every nuance) beforehand?
..... but I wouldn't go quite so far as to assume that!
See also:http://www.elevenplusexams.co.uk/appeal ... cation#b40
(Even though this is in the non-qualification section, some of the points might still be relevant.)