There is a specific kind of frustration reserved for a British winter. You are standing on your own doorstep in the pouring rain, carrier bags cutting into your fingers, rifling through pockets for a key that has mysteriously migrated to the very bottom of your coat. We have all been there. The promise of a smart lock isn’t just about high-tech gadgetry; it is about the simple, profound joy of your front door recognising you and swinging open before you even touch the handle.