goodness - never heard of that one before - and I thought it was bad in Torbay. If it's not written in rules at the beginning of the exam (which most things are!) then I'd think you have a very good case?
I agree, unless the children were clearly told at the start of the test that they shouldn't write on the paper I think you would be quite justified in appealing on those grounds. The instruction should also be reinforced on the pages of the test booklet as children can't be expected to remember everything they are told in a stressful situation. A lot of children would be mortified at being criticised during a test and would be completely put off concentrating. If it doesn't upset your daughter, get an account from her now of how she felt when it happened, and get someone independent to sign and date it, as the appeal date might be quite a long way in the future.