I too am appealing to a Glos GS - hearing within 7 days of now (eek!)- and I have not received a copy of anything submitted to the panel by our primary.
It may well be that your primary have not sent anything in to the panel. I'd say that 1/3rd of Glos primaries send in some statistics to the panel (some or maybe all of: predicted SAT scores, Y5 CAT scores, Reading Age - not all schools do CATs). Some send a nice letter of 'support'. 1/3rd send nothing. We do not put any weight on lack of information from the primary it could be a head who does not support grammars or they may have a policy of not favouring any appeals (support one & you have to support them all no matter how worthy). Don't panic!
You could 'phone the clerk and ask if they've received anything, just to double check and put your mind at rest. If the worst comes to the worst (very unlikely), and you've not received something submitted, you can ask for an adjournment so you can go out & consider that information before continuing the appeal.