Another update - returned to VW Blackburn today to check the positioning of the antenna. They've now move it higher to the vent arm position. The mechanic didn't know the antenna was magnetic!
If anything, its slightly worse now
I left the unit on when i got home and it didn't find the car. However i was parked between a car, van and building. I then went to my mates house which is on the side of a hill and left it on. Hey presto - found the car no probs. When leaving i set the nav to take me home and as soon as i set off it said i was going in the opposite direction!
Is it possible to plug the antenna into the wrong plug on the back of the unit?
Is there more than one type of antenna - could i have the wrong one as a new one was purchased by the seller?
I'm going to the RR event in Halifax next Sat and i'm hoping Darren will be able to coax some accuracy out of it!