GPS, DAB issues

[Freddie0]

Had my 2013 A5 for over 2 and a half years hassle free so far, but over the last few weeks have started with a couple of issues which I am assuming are related.

My DAB has never had the best of signals and now nothing at all. In addition my Nav locates me miles from where I am. I have tried the 3 button restart, also a power reboot, and been through the menu to put in the location, but it still has me elsewhere. Not just the same location either as it seems to vary.

It also seems as if my FM location may be week.

 

I don't appear to have any OBD codes recorded or historical, but my best guess is that the shark fin needs replacing - would this be about right or does anyone have any other ideas? Thanks