You're in england, and most of the people posting here are from america. Right wing over here means something very different from right wing over there, so I would have to remind you of that before you rely too much on advice from americans.
I was under the impression they subscribed to the same grossly disproved economic model that has been repeatedly shown to self destruct and fuck everyone up the ass since it was first introduced in the mid 19th century. The "Jesus are capitalisms and haet poor people!" elements are unique to American Baptists though, I think.
Also, in my experience, most people will have made up their mind on issues like this before you say a word, so even if you give a much better argument than the other bloke, it may not count for much, if anything.
It's a formal debate. I don't know the specifics, but I basically gather it's a verbal pissing contest, with the winner being whichever one argues the most convincingly, whether or not what they're saying is true or the judges are actually convinced by their position.
Best of all, if you're really just supposed to argue against left-wing economics, rather than FOR right wing, CHOOSE THE THIRD ROAD! Watch them flop around like a fish out of water. Even if you have to argue for right-wing, argue for an interpretation that isn't in line with what they expect, and you'll have quite a bit of support not because your arguments are good, but simply because they are at odds with what your opponents expected - they will often try to fumble the critiques they had planned before hand into an argument where they are not applicable, and this makes them look weak and your look strong.
Did this when I was in secondary school on a topic of "Will robots conquer the world?" (essentially transhumanism). It was hilarious to watch people squirm as I accused them of the same basic concepts that the Catholic Church had during the colonial years. :p
Out of curiosity, what were your arguments there?
Play the part of a right-wing pundit. Lie, make up random shit, claim to be Jesus, claim to be Martin Luther King, cry, more messianic shit, scream 9/11 a few times, cry some more, accuse your opponents of being traitors, communists, nazis, aztecs, atlanteans, jews, celts, bankers, pedophiles, murder victims, jaywalkers, hyperboreans, various egyptian gods of death, valkyries, admit you're just pulling random names out of your ass, accuse your opponents of being communists for not doing so, cry a little, and insist you were just getting into character if censured, then insist you thought you were in drama, and were supposed to play a bit part. At this point, the judges will either be laughing their asses off, or extremely pissed off, so claim to
actually be providing an object example of a
leftist pundit, to show why your opponent is wrong. You will either win through the sheer audacity of it all, or lose. And isn't sheer, mindnumbingly insane audacity more epic than actually trying?
Or just claim to be arguing in favor of right-wing Equitarianism, wherein all economic decisions are to be made by horses, who are obviously Perfectly Rational Beings. Provide a picture of a horse smoking a cigarette and reading Atlas Shrugged. Plus points for speaking in a fake russian accent.
On a more serious note, toe the line of the rules. Engage in logical fallacies as subtly as possible, appeal to personal greed, attempt to foster resentment of mythical exploiters of a socialist system, insinuate that your opponents are making things up, while making up examples to support your points (they can't have a response ready to refute something they've never heard of, after all). Invent a philosopher/economist who totally said something memorable that supports your points. You're not going to convincingly argue right-wing economics otherwise.