I killed it!
I was on a boat in Sardinia, and when taking off (the 3rd time in that day) I got a momentary notification saying IMU error - but it disappeared. I then got the all clear, took off and then drone drifted and hit some cables and spun into the water.
20 minutes later it was...
I just upgraded the R/C Firmware 07th Sept 2017 and now the remote will not charge at all, I have tried 7 different USB cables and none work even though they work to charge other things, battery is now at 10% because it was " On Charge " all night so not even enough power to Factor reset on DJI...