Another bit of useless information which shows how things are written without proper thought being given to them.
When the building regs were first written about switching heights they included the mounting of cu and stated that the cu would require to be fitted with a suitable lock to prevent unauthorised access (children primarily). It was then pointed out that this could create problems in the case of lighting circuits tripping at night and so the lock requirement was not included leaving another total "cock up" for us to cope with.