Christian McArdle wrote:
What is the accepted/normal/safe way of dealing with this? Are there
any sorts of locks one can have which are secure but always enable the
door to be opened from the inside in an emergency?

Fit a security latch, such as a Yale PBS1. However, these are only secure if
there isn't an easily broken pane of glass that can be reached through to
open the door. If there is such an arrangement, then the handle needs to be
locked and you are back to square one.

No, it's a pretty solid front door with no adjacent glass, the only
risk is the letter box and I'm sure we can make the latch far enough
from that to be inaccessible.

That seems like the solution, thanks!

--
Chris Green