There is mention of the key in the statements and it wasn't a standard (Yale) key.
Had you read my posts properly you would realise that I was aware of that.
The issue I have is:
The frigging unit is a bog standard combo dead bolt and spring catch common all over the world
The dead bolt may be operated by varying locks. This one is a cruciform lock, as common as muck in Europe but the average person on this forum judging by ccomments, thinks such locks are rare having somekind of voodoo properties and deliberately fitted in properties in Portugal for nefarious reasons.
The spring catch is no different from any other external spring catch but because most people only look at spring catches on their sitting room doors have no idea of what an external spring catch looks like and how it is fabricated to comply with the standards; again the thinking seems to be it has magical properties because "I have never seen one like that before"
The facts in this instance are:
Provided MM could operate the thumb slide on the spring catch she could leave the apartment.
Unless the the spring catch were held permanently in the disengaged position she could have been locked out.
If a double cylinder anti-lock out lock operated the dead bolt, these are as common as muck throughout the world especially used on accommodation for vulnerable people. If one was fitted then a cleaner could gain access even you had if you had stuffed the key in the lock on the inside cos that's 'ow the bleedin' thing's supposed to work innit? If there isn't a double cylinder lock fitted then the tales of the cleaner etc are hookey.