Go for it, ask Kent Council if they do a re-mark, Medway dont, but I think some councils do, I enquired about this last year and I think Kent may be able to help.
The school I was on the appeals panel for always did a manual re-mark of answer papers for children who were subjects of appeal.
Back in May, for the first time I can remember, one paper was wrong - one question was marked wrong instead of right. The child was 1 point under admission, which changed to one above. We didn't get to hear the appeal, as the clerk told the school that they must offer a place (this was the morning of the appeal, and she managed to get hold of the parents by 'phone before they left home).
But don't forget, a manual remark could also find a question marked as correct when in fact it was wrong!