A key copy is a key made to match the original, with the same cuts and the same profile, which opens the same lock. It is what people ask for when they want to give a key to a relative or to whoever looks after the house.
We do not copy keys. We are telling you this so that you are clear about what a copy is and what it means.
Every copy that leaves your key ring is an open door that you no longer fully control. In holiday rental properties and second homes on the coast it is easy to lose count. The way to keep it under control is high security lock cylinders with a key security card: without that card, no new keys can be ordered. And if you suspect there are spare keys out there, the sensible thing is to change the lock cylinder.