Unless Jack bribed the judges to give him a high score, there was nothing suss about his winnings. In fact he doesn't even know yet as he is not on the internet, and has been away.
I have only known the winners names just before the show, as prior to this it was all based on bottle numbers, and class number (no names are attached to the bottles for fair judging).
What he has done is no mean feat however. For the beers, it is the largest number of submissions, and he brews from a kit. When the judges scored his winning beer (Stout Modified Kit), they were of the belief that it was all grain, but I know this is not the case, so even though you cant read this Jack, congrats!
I don't know much about Ginger beer, but his winning entry had a beautiful head on it, that I don't recall seeing on a GB previously.