Discovery 3 - Nav / Phone problem

Right well the other day driving down the road using my sat nav. The man who speaks cuts out. It cuts the music like normal but nothing is spoken.

So i have a fiddle etc and still nothing. I phone up the dealer while im driving thinking i can ask them but my phone is working and i cant hear them though.

It turns out my Command button isnt making a noise either nor is the nav or phone.

I turn it off and back on again giving it a reboot and it works fine. Well its now happened again.

What im asking is has anyone come across this before? If so what was the resolve?

Sounds like a plug has worked itself loose whilst you've been driving -

best have a wiggle round - it's got to be the cheap option