I read that on the BBC and my immediate reaction was to re-read it just to make sure I was reading it correctly. After that my reaction was "You rock" followed by "If I didn't fancy ****ing off the Gurkhas before, I certainly don't fancy it now"
Or perhaps the blunt trauma to his cranium gave him memory lapses. I can't remember if it says but did he get a confirmed 30 kills? or just held them off?
Per the article, he made it through the experience without a scratch (ergo no head trauma). While the article states he held off "up to 30", I'd be inclined to take his word that the number was around there...these guys seem to be pretty straight shooters (ha!), and not likely to exaggerate what they've done for the sake of a medal.
Also, I'd say that the fact that his commander(s) recommended him for the honor suggests there was pretty hard evidence that the number of attackers was spot-on.