To an extent these events of cowls not being latched and detaching from the aircraft over circa 30 times with a number of different operators reminds me of the phrase coined after the Space Shuttle disaster after the O ring failure, namely "normalisation of deviance". (This is no criticism of BA and their procedures but if
all these events happened with
one or maybe
two operators then
maybe there would be a bit more joined up thinking as to devising a bullet proof system which means this can
never happen again)
As professional aviators and engineers involved in flight operations we all know how important various checks are but are also too aware of our own limitations when doing such items especially when under pressure of quick turnrounds etc.
If I was in AIB I would be looking to recommend a physical fix to ensure this can never happen again.