Spare keys

Strange thing. Went to make a copy of one of our keys and they said 'no can do'
Apparently, the key has some security numbers/letters and they are not "allowed" to make a copycat

Has anyone went back to their builder after a long time (months and months!!!) and asked for duplicate keys??

before contacting builder, do as I do when I don't get the answer I want... try somewhere else first.

I would if the builder gave you a master key my accident.

Yeah, I need to find a more "corrupted" key cutter

But what do you mean with the master key?

I think B Star may be right - if you find another key cutter says it is a key that can't be copied, it sounds like the builder accidentally gave you a copy of a builders key at handover. Builders have master keys called "Builders keys", which means that houses under construction are all keyed alike with that key, so that the SS and trades can all get in to any of their houses. Normally you'd be given your own keys at handover, and as soon as you put your own key in the lock it overrides the memory it has of the master key, so that the builders key will no longer work on the house. If you do have a builders key and you had handover a while ago, the key you've got is probably useless on any other property as they change them reasonably often... but you should probably contact the builder to get a real set of "copy-able" keys!

I didn't think we were given the master key. We got the keys in a sealed envelope, and I went around the house and "turned my new key" at every door with the SS watching.
We do have another same key, but it's "not at home" ATM.

... goes away too look for a stash of keys to check what's written on them ...

Oooops ... how embarassing! Just went and checked other spare keys that the builder gave us and found another 3 copies of the same key (they all have numbers on them)!! Plus copies of another main key ...
So we don't even have to make copies (yet ... in the meantime, we should look for a corruptable key cutter ).
Apologies for your wasted time in responding to this thread!

Lockwood introduced a restricted key system to all their new locks, you can get one directly from Lockwood.