find if my car has a tracking device fitted to it?

This happened to me a few years back, they fit them or hide them behind the glove box next to bulk head, why there? because its dry and hard to find. You cant not disable them because it flags up to the scum bags who Fitted it. They should have told you before you start job that you have a tracker on the car rather than trying to catch you out or not trusting you.
They can check speed time and when you stop, and even back date to any day in the past all your driving record and to within feet of where your are in the uk.
My advise, look for other job. (I did) Or put up with the spy in your car.

Company car sales man
January 2009

As you give so little information it is difficult to help. Fitted by whom and for what: e.g. Stolen car tracker, Police, Security Service (MI5), insurance company, private detective, WHY? If I was you I'd ask the person who told you that the device has been fitted who did it and follow up from there.

t
June 2008