Ride out tonight with phone running strava and screen permanently on and connected to the lights battery box. Phone battery was at 84% when I set off and is now at 100% after an hours riding with the double cree light on at full.
I stopped to check the map situation and found it was logged I into someone's 02 network.... and map was as normal..
Looking at the strava upload it is just as if I had used the garmin.