Welcome - and thanks for your email.
As far as evidence is concerned, I'd enclose the letter from your employer. Take the other evidence (council tax bills, etc.) with you to the hearing and tell the panel they're available if they should wish to see them. They probably won't - the fact that they're available is likely to be enough. (No need to 'overload' them when they're going to believe you anyway.)
Try not to spend too much time on the admission rules when they've been correctly applied. I quite like your approach ("They weren't really designed for this situation
I'd avoid being too emphatic about the journey to the allocated school. By all means say that it's "undesirable
", but not that "It can't be done
" because the panel may well know that there has always been a contingent of children travelling south from the north of the county.
Take care that your appeal doesn't become 'unbalanced'. Ideally it should focus at least as much on positive reasons
for the school you want as on negative points to do with the admission rules and the allocated school.
You are right that academic evidence isn't relevant when the child is qualified - unless it relates to the school's specialism. (Schools are no longer funded for this, but no doubt they still have a lot of residual expertise.) See C2 (vi):http://www.elevenplusexams.co.uk/appeal ... -school#c2
Friendships could be a good point - but be prepared for the possibility that you might be asked how DD coped when abroad.
You don't need to write at length on the appeal form. Keep it clear and as simple as possible.http://www.elevenplusexams.co.uk/appeal ... school#c18
Give some thought to how you will sum up at the hearing. You need to win over the panel at an emotional level (how much DD wants to go to the school etc.).http://www.elevenplusexams.co.uk/appeal ... school#c32
It's certainly worth appealing, but you will need an element of luck. Hope for a sympathetic panel, and that there won't be too many other appeals with strong cases that might overshadow yours!
Do let us know if we can be of any further help.