Hi how do I stop my Avata disconnecting while in flight it will just sit and hover I have to turn the controller of and back on for it to reconnect

Hello, there. Sorry to hear about the situation. Did you encounter an error message on the DJI Goggles upon encountering this disconnection? Please make sure to fly your aircraft in an open area away from interference with strong GPS signals. I hope to hear from you soon.

No nothing at all the view in the goggles just freezes and that’s it no warning no errors nothing sometimes if I can walk towards the drone it will reconnect but not every time

The first time it happened I was under power lines I thought fair call on interference from the power lines but it’s been doing it in open places as well with full line of sight

Mine has done this once.  I was still able to fly the drone but without the use of the goggles.  I did a refresh of the firmware using DJI assistant and haven't encountered this problem since.  
May be worth a try?