I read somewhere, long ago, that Petter refused to put bulged landing gear doors on the Gnat which would have been needed to accommodate the size tires needed to meet the NATO Field requirement (grass air strip?). There may have been other requirements He did not want to change the design for? This would have knocked it out of the running well before any fly off took place.
I think it was something by Bill Gunsten but could be wrong. Doesn't mean he was right either.