The invisable man keeps moving my satnav!

Hi everyone, I am having a problem with my 2017 Grand C-max navigation.  I bought the car in February from a main dealer and it had to go back because the arial was missing of the roof.  They fitted a new one but it didnt help my problems with the sat nav, to cut a long story short the navigation was cutting out screen staying black etc and they have slowly replaced all sorts of parts which have sorted all the problems out but one.

When I am driving with the navigation screen up and your location is in the centre of the screen, its as if someone has just touched the screen and selected a side road.  It then stays on that point until you re-centre the screen.  Interestingly it always gives the name of a small village near me on the bottom of the screen regardless of where I am in the UK when it happens.  The problem is when it does this it will repeat it every ten seconds or so until you restart the car.  It will not happen everytime I drive it but it will happen a few times a week.  My Ford dealer are now getting less helpful and I understand it must be an infuriating problem for them but its pretty infuriating for me having to buy a Garmin to stick to the windscreen just incase.

I wondered if anyone else has experiance of this or has some advice, I was thinking do I need to buy something special to clean the screen perhaps?

Any thoughts much appreciated, I should also mention everytime the car has gone in to be looked at they have reset it and updated it.  I have also attached a picture of the screen after it has moved off my car, and I was in a car park at the time so the red arrow is in the correct location.

Many Thanks