Hi, just thought I would share this with. I haven't owned my 307 03 very long. When I got the car the key fob was missing one of the buttons so locking/unlocking was via the key. Sent of for a key shell and when it arrived I swapped everything over and, following advice from a post on this forum, I reprogrammed the key. It took a while to get the fob working and when I checked the circuit I saw that two connections on the micro chip had a build up of corrosion across them. Cleaned it up and the fob then worked ok, or so I thought. I went shopping the other day and I could not lock the car, either with the fob or key. As fast as I was locking with the key it would unlock. Anyway, to cut a long story short, it turned out to be a fault in the circuit within the fob. I removed the battery which cured the locking fault. I can only lock/unlock via the key, but hey ho. I don't have the security card so I don't know if I can get a new key. But at least I can lock the car. Just thought that this may be of help if anyone else is having the same problem.