In my experience the plate makes no difference to value unless it was itself worth a lot (££££s for example). This is not a rule. Remember that a DMC plate will be worthless to everyone but us (I saw a lovely N plater Porsche 911 yesterday with DMC on it, to the owner? worthless), the same goes for cars such as M3 BMWs, we've all seen the plate M3 BMW advertised haven't we?
There are plenty of those plates (DMC) about so I reckon we should all get them....!
Good luck,
Dan, Vin#5641 "Maddie" (Not going to Ireland.....<whimper>)