Thanks for that – it’s what I thought, but I wanted to check as we all tend to bandy around term that turn out to have a different meaning for different people.
Regarding the lock, I spoke to a senior firey some years ago and he said in a case of a genuine emergency they used the “big red key” … meaning an axe.
Whatever you do to change the locks is probably a by-law breach, but nevertheless, leave a spare key with a responsible adult who lives or works in the building.