This is what the tracker I removed from an E Class looked like:

Click image to enlarge

Thank you ALX! Sure will help when going to search for it next week.
Is it the white battery on the left of picture and the black small Motorola thing in the middle?

Yep, the battery is glued to one of the modules, the Motorola thing is an aerial. You may as well have only one of these modules with everything integrated, not two. This tracker is from 2003.

Thnx again ALX! Was your tracker marked in any way or did you have any other clues so you knew it was a tracker?

It had a couple of meaningless numbers (like 5TRK0101UK. TRK = tracker?), which didn't produce any results when I searched the web. One number pointed to a discussion thread on some Honda forum where the owner was basically asking what these were as he found them in the car with people suggesting it's a tracker.

yesterday several hours of looking for a tracker...... nothing! Checked rear wheel arches, front foot wells, removed top dash, checked under bonnet....nowhere a sign of a tracker