Let me try and make this clearer as all the questions seem to suggest people aren't joining the dots or I am useless at explaining stuff.
The police had made a raid on some premises where they suspected people were up to no good. This was nothing to do with my car or anything they knew at that time about my situation it was due to other stuff they were watching/doing/investigating at the time. During this raid they found cars in a state of breakdown and also some laptops. On those laptops they found some tracking software, which they accessed and at that point were able to see 2 cars being tracked, of which one was my RS4. At that point the police sought to locate those 2 cars and the owners so they could establish evidence of a tracking device. THIS is how the police go to me.
Added to this, they were able to establish in detail the movements of my car since the device was added and in doing so establish where it was added, Birmingham International Station where my car had been parked for 3 days. Worryingly they were also able to print off a junction by junction map (around 50 pages of A4) of my movements, speeds direction of travel, significant course changes. When they knocked on my door they had lost the track of the car (it was garaged) so were unsure it was mine, but the last reported location was on my drive, some 50 yards from my house. They asked some questions, I made them aware of some friends who had visited that weekend in high performance cars and that it might be them, but they felt it was someone who lived here, but we left it there.
About 1 hour later I got into my car, reversed it out of my garage and the pings started again on the devices the police had. My phone rang, the police officer dealing asked if I was in my car, which I confirmed I was and at that point we had strong suspicion it was my car. I parked it on the drive, officer turned up 30 minutes later and we then went in search of tracker, see pictures above. THAT is how we got from knowing nothing about it to knowing about it, which should be clear for you all now. I also arranged for a local garage to give me access to their ramp so we could get it up and have a proper look as the officer was struggling a little. During this time 2 traffic officers came in for a new tyre (Tax Evader it was your mate!) and I then had 3 officers all nosing over my car.
They also knew that on 2 occasions the criminals had tried to locate my car and had driven to where I lived or close by trying to locate my car, don't ask me how!! A neighbour also witnessed said people and reported it. None of this is secret information now as it's in the public domain after the court convictions and I knew all of this at the time and more which obviously I was not going to go into. The 4 perps were sent down not just for my car being tracked, there were other convictions too, mine was just added to the list.