When we bought our Aztec it came with two keys, but only one was the "full function" fob with buttons for the imobiliser and alarm. Being risk averse and convinced that one day I'd lose the important key, I wanted another
I know they are expensive from main dealers but we found Paul online, phoned to make all the arrangements, and when the blank fob arrived (only took a couple of days) he came to us to set it up.
He's based in Keswick and travels all over Cumbria. If you wanted a spare but were not local I am pretty sure he would meet you at a campsite, however, we did have a chat about the security implications of 'fixing' vehicles in car parks and so on and he insists on seeing proof of ownership such as V5, insurance documents, etc.
Cannot recommend highly enough, no affiliation, bla bla bla. Paul arrived exactly on time, was really pleasant and let me loiter around and watch! The new fob works perfectly and having a spare gives the peace of mind I wanted.