Jaguar XF 2011 facelift sat nav issues

Hi, My XF sat nav is well out of date and the upgrade available on the usb stick was not recommended so I decided to use a Garmin I had. It picked up satellites when placed to either the far right of centre or to the far left of centre (no good whatsoever)  but lost all satellites when placed on the centre of the dashboard directly above the info screen. However I prefer it in the centre of the dashboard and thought it may be the sat nav which was at fault. I purchased a Navpal model which does exactly the same. You can see the satellites disappearing if you move it from the left or right back into the centre.  I assume it is related to the inbuilt sat nav. Anyone ever come across this issue before? It’s pretty annoying especially as the built in one is so out of date. 
thanks in advance..!