Interesting that Airfix would have offered this 'feature'? I would think that separate flap pieces would have been more appropriate given what you just described. I suppose there are some who build 'wheels up' and while hanging from a ceiling string, the ailerons would be a dynamic visual addition. I will leave mine as is as it is not 'wrong' technically, but unusual.Actually it is quite difficult to state. In most pics it can be noticed thatthe ailerons were set neutral when on the ground. But usually there is somebody in the cockpit. Of course there are images without any in the cockpit sitting and the ailerons are not in the "actuated" position too. So we may assume the neutral position of the ailerons was the "usual" setting while the deflected ones happened quite rarely.