Re: Confused about keys!!!!!
The red keys are too old for your car. You should have two black keys like you describe. They should be the same, there is no master key. If you get another key, then you need the code card. UK supplied cars did not come with the code card but you can get this from a dealer (at a cost). The car is programmed to match the keys, not the other way round so Timpsons cannot do it. It seems that many dealers will claim that second hand keys won't work, but chat on the forum suggests this is cobblers.
I believe that you may need to get a key from the same generation. My 2001 156SW has system 3 keys (stamped on the metal blade next to the triangle) and your's probably is system 3, too.
All credit to other people on the forum. 90% of the above info is gleaned from other people's postings.