In the end, with a redesigned housing for the PCB, and while retaining the backup mechanical key, the new fob is just 11mm, down from 18mm – a nearly 40% saving in thickness! It’s a tidy way ...

This has space for up to five mortise or six to eight Yale keys, plus a car key. It also allows you to re-set the four-digit combination at any time, so if you have a holiday let or AirbnB ...