I've unfortunately exhausted Google.
I only ask because the name D Coulthard, with signature, is present in my car's paperwork and in the log book too. It would be nice to confirm whether or not it was the "REAL" D Coulthard.
MyCarCheck also showed that quite early on the car had the registration "R6CEY", another thing that fits the bill. That number is currently on retention. Would be interesting to know who owns it.