Thank you for your astute, well constructed observation and invaluable advice SLFguy.
You obviously think that Pprune is more influential than it really is. The discussion here is interesting, and the exchange of views and experiences is useful in as much as we come to realize that our individual experiences are not isolated, but part of a long string of inconsistencies perpetrated by the security contractors at UK airports. My point is that the people who need to know about this state of affairs will not be reading Pprune: they have better things to do with their time. If we want things to change we have to send carefully documented reports of each incident to the People In Charge. This applies equally, albeit separately, to crews and passengers.