Having now sold my SL55 I have the reg no. on retention. Not done this before but a quick look at the DVLA site and it says it costs nothing to assign it to another vehicle. https://www.gov.uk/personalised-vehicle-registration-numbers/keep-or-assign If you have a V8 Merc SL you may like to add a finishing touch. £500 + any fees, if there's any I've missed. Thought I'd offer this to interested parties before it goes on Ebay. Please PM if interested.