Interphone & Google Maps

So I've got myself a nice Interphone sport, it works fine for receiving calls, playing music and talking to my riding buddies (although the range of 1km is absolute bull).

The problem I can't figure out the answer to is using Google maps while riding. If I setup the route on my phone I can hear the voice command tell me to take the first road or whatever through the Interphone, so I know the Bluetooth is working, but as soon as I lock the screen to put the phone in my pocket, the navigation stops.

I've tried all the Bluetooth settings, 'leave phone unlocked when Bluetooth is connected' and on maps 'voice commands over Bluetooth' etc but nothing seems to work.

Anyone have any ideas on how to make it work?

 

Tried this on a hire car and had exactly the same issue, voice commands works fine when the phone is open but when locked it stops so clearly a phone config issue somewhere ...

 

Mine is Android so the menus are different but I think I found that the problem is, when the screen is locked after about a minute the navigating is stopped, maps is still running but now waiting for you to start the navigation again.

I just found a setting in battery saver options that Google maps was on the list of apps to 'never run in the background' so I guess the battery saver is putting maps to sleep after a minute.

Removed Google maps from the blacklist and tried it again and was still running after 5 mins of screen locked

 

Exactly, all those 'advanced features' don't always work to your advantage