Our post was a bit unreliable so we hired a PO box. We did that about two years ago. As there were none of the little lockable boxes available we've just collected our post from behind the counter all this time. Last week a new set of real boxes arrived - numbers, locks, everything - very smart. "They haven't sent the keys yet though!" said the chap in the Post Office. This week there was a key. "But we only have one so you'll need to get a couple cut for yourself and then return the original."
I did, I have.