Okay, I have always used the whip to retighten as well so as not to stress the hub, never really thought that 40nm is probably less than my massive leg strength
Assumed that as the wheel was held when tightening the lock ring then the force on the wheel was greater than when it was allowed to rotate under normal riding conditions... but then doing a track stand applies loads of force... but then with a disk brake and track standing the hub is braced....
I'll stop now, clearly I need to think less and ride more, thanks for the replies.