When I bought our new LCR last year we bought a second remote key to avoid arguments. I suspect the same precedure will occur here;
Pay for new key (remote was ~£90, not sure about the standard one). Stealer applies to Seat for a new code (computerised system) and reprograms all keys and the car at the same time. Need to take the dash off to do this so takes a while.
We didn't get charged any labour but I suspect that's just because I'd just spent a load of cash with them
Ian.