Any dealers that would trade down a car?

Most will do it if it's a popular car in demand, however you won't get anything near it's true value from them. You will benefit more financially if you can sell it yourself privately though it does involve having to deal with messers and weirdos.

The problem with a car of that value is that most people do not have €14K to hand, a lot of people buy cars on tick, and those with 14K may prefer a dealer guarantee. So the ratio of messers will be higher.