Unless BMW do you a key (at a cost of around £200) using whatever official interfacing methods they use, any locksmith, you or me would need to remove the EWS to make a new key. And most will still charge £100-£150.
The EWS is the small security control module near the steering column. It’s 10 mins to get it in and out by removing the underdash panel.
There are people on eBay who will cut you a new key, supply a PCB and program the chip for about £80. But as for an auto locksmith the key, buttons, case will be a Chinese copy (possibly with a donor original PCB) and won’t quite have the same feel to it. You will also need to send your EWS in the post. So a security risk sending it to a stranger, it may get lost in the post and you may have less comeback if they damage it. The process carries some degree of risk.
Most people opt for BMW taking all the above into account. Or if they are stupid like me spend around 60 hours understanding how it all works, buy a programmer and start making their own. I can’t cut keys. But I get them done for £15.
I would still be trying to get your old key to work.
Does the key still start the car? If it does I’m confident we can get you back in business with a PCB only. A new battery and a resync.
I have a personal supply of tested 3-button PCBs. I can send one for £15 posted. And will provide help to get working by PM. I wouldn’t normally sell these but I’ve done all the keys I need for now and have a few spare.
Im also sympathetic to domestic disasters involving dogs. In fact I’m replacing a chewed door frame and architrave from when they were puppies 6 years ago. It’s taken me that long to trust they won’t do it again