Gilberto
Look at the cars in the main dealers that are closest in spec to yours , that will give you an idea about the value a dealer hopes to achieve from a sale.
For a private sale you will need to deduct some thing from this , how much is a really big debating point. The dealer has to offer a warranty , pay VAT, and make money on the deal, so that margin is substantial.
Sorry to hear about your need to sell, but good luck with it.
