Take all of your UK paperwork to the customs office in Fethiye,go into the first or second office on you left as you leave the street,there they will give you a form to fill in,its in English,also a number of the staff speak English,you will need copies of your passport,residency,maybe Tapu,I can't be sure,they will tell you,I have found them very helpful.
Your car will be left where you say it will be,your home?not at any air or sea port.and nobody else should drive it
There is no cost involved apart from your copying.The form issued is meant to be shown at Passport control when you leave Turkey,normally they don't even look at it
They do close for lunch.