I am pretty certain special laws are in place in Great Britain.. wherein any mechanical device has to be run by the Queens inspectors.
ANY part which is too easy to work on, or has too few moving parts has to be redesigned to meet the "english madness" laws.
So mechanics and such can make a living wage since no ordinary person will be able to fix ANYTHING.
I am certain that is the reason.
Also, all those inspectors used to work for Lucas, or were trained by Lucas engineers.. So that might be a hint of what kind of 'tomfoolery' they will add to make stuff impossible to work on.