Can Bus alarm as alternative to new remote locking key?

[MysteryLemon]

We've just purchased an '08 Fiat Bravo. Lovely car but only came with one standard key. The car has remote central locking and Fiat apparently want around £350 to supply a new coded remote key... Timpsons wanted £446!..

What are my options with regards to installing a Can Bus alarm to run the central locking system instead? I see most can bus alarms don't come with a fob as you're supposed to use the genuine remote key to operate the lot. Some do seem to though I think. If I buy one with a fob, will I be able to use the alarm fob to operate the door locks? How plug and play are these Can Bus alarms? I've installed analogue alarms on older, non can bus cars in the past. Never really dealt with Can Bus before.

Failing that, is there any can bus central locking control system available? Can't seem to find much about.

Thanks

[Craikeybaby]

Generally each manufacturer runs their own implementation of CAN and change it slightly every few years, different message identifiers etc, so it would be hard to have an aftermarket system.