Exactly what big chez said.
£5k a year is what, about £80 a week after the dreaded? Are you currently struggling to run a car and phone so that you'd NEED them provided?
If you love your job selling cars and didn't particularly like valeting, get a job 2 evenings a week delivering pizza!
You WILL NOT be on £14k for ever if you're any good, just look at the salaries in the back of the trade magazines and keep your eye on the future
You get one go at life [unless you're a buddhist

] so why spend it doing something you're indifferent about?