I've got am idea, which may be more worthy of lobbying the powers that be about, than trying to get security restrictions relaxed:
If we (grudgingly) accept that unfortunately the current security restrictions are going to stay in place for the time being, then what we really need is a scrict 'code of practice' for the security guards. In fact I would go further and wrap it up in some "human rights" context.
If a person deals with the police, as a suspect, as a criminal, as a member of public, then there is a clear and well known set of rights that both sides have, and very strict sanctions if either is broken.
This is what we need at the airports. These security idiots currently break the law (assault, sexual assault, verbal abuse, various means of obstruction) with impunity and yet if we even dare to question then we loose our pass and means to earn a living.
So what we really need to lobby MP's and transec about is not for a relaxation of the security rules, but a strict code of conduct and set of rights for the passengers and crew (and yes, the security prats), and a strict, written down, list of exactly what is and isn't acceptable, so that we don't continue with being allowed to carry yoghurt one day, but not the next.