[mattSV]

I have traded two for one before - I traded a Citroen Synergie (7 seater MPV) and a Ford Escort Mk5 Cabriolet for a Saab turbo convertible from a non franchised dealer.

Going to a main Ford dealer might not help as most would not put an M reg Fieasta on their forecourt - most would trade it straight out, or auction it. Likewise with the Scenic, unless it is less than 4 years old and low mileage.

Your easiest option is to chop them both in if you can find a dealer who will do that, you will make more money if you sell them both privately but it is usually more hassle e.g:-

Having to spend time/money tarting them up
Having to spend money on advertising
Waiting around for tyre kickers who never turn up
Selling both cars and then being without a car at all until you get a new one