you should easily get 15 k for it mate,
dont let anyone else drive it but you if you have to.. and get some pepper spray in your pocket. Also take some golf tees, put them inbetween your fingers and clench a fist they act as spikes should the viewer try anything dodgy. If they come with a partner, hold the partner as hostage, tie them up put them in the basement then say to the main viewer "...okay let go out and drive, but be warned, if I am not back you will not see your partner again"...
All the above is mentioned in the Parkers guide how to sell your car.. page 3 I think