Not something I've been involved with before. My MiL has asked me to sell the plate that was on my FiL's car until he passed away last summer. It's only worth a small amount so far as I can tell, but better in her pocket than not.
MBZ then four figures. Was previously on a merc. Unexciting, but they seem to change hands for between £400 and £1000 depending on how interesting the numbers are. I suspect this one might be at the lower end.