I was given a key and a list of codes for all the internal door locks.
I went there and let myself in.
Five minutes later the joiners turned up. They had a key and a list of codes.
Twenty minutes later the alarm people turned up. They had a key and a list of codes.
Thirty minutes later the plumber turned up. He had a key and a list of codes.
One hour later the NHS maintenance man turned up to let us in. He had not got a key or a list of codes.
Still. I'll give him his dues. He waited with us all day so that he could "lock up". He did this by borrowing my key as I was the last one to leave.