Thanks. I think it must be the animation that is the problem....I saw the animation for destroyed or damaged but didn't check the stats that closely....then the bomber 'reappeared' without detruction/ damage.....At least I know that it is just hard to kill them and that the ai isn't cheating as well!
It does seem to me that the damage modifiers really affect these early planes esp. Spitfire, Me 109E etc. I guess the effect is proportionately greater with these although I haven't flown much with later models. I need to try BoB as Axis to see if they really have an easy time or it is my poor play..