I don't really suspect an air leak, that would be causing revs to rise, not hard to start issues (unless you haven't seated the carbs).
Dumb question, but how reputable is the service shop? You trust them enough to know that they changed everything for you? The NSR airfilter is not something that any shop would have on hand unless they made one from a foam piece.
hmm I will chat to a few kiwi work mates and see if they have carted anything over the ditch back home. Bugger about the Bendigo bike, is it really worth shipping over though?