not all gloom
Depending how recently you bought it you could still get the complete system changed for nothing.
I bought mine in june, without the red key.
I phoned the dealer after 4 days, After reading the hand book, and said I was concerned.
I spent two weeks of trying to find out exactly what the situation was. The only certain thing I found out was that without the red key the car is legally considered defective under the trade descriptions act. And therefore you are entitled to expect the seller to rectify the defect, come to some other compromise or refund you all the money in return for the car.
At that point I wrote to the dealer stating that. They wasted a couple of weeks trying to locate the key and trying to convince me it wasnt essential, probably hoping I would go away. As I didnt, they eventually replaced all locks, ECU and code box in order to provide a red key.
It wasnt a great deal of hassle but I did buy from a dealer that had some ties with a fiat garage. Dont
know whether that helped.
Bottom line is. You are entitled by law to expect the above. How much hassling you have to do depends on who you bought it from. Obviously keep tight control of any
all correspondance and get receipts for anything.
good luck if you pursue it.