So the one key works but the immobiliser doesnt turn off for the second key??

 

Any clues?  I've heard the immob' can be temperamental like.

 

Cheers, Matt.

It's probably a spare surf key to open and close doors etc in an emergency more than for daily use  

Unless its a programmable key, it won't work. From new, you get three keys. Two Proper ones and a valet key that allows access to the car but it will not enable it to be driven with it!