vive Pro + wireless adapter flickering Eilite dangerous

[Masrock]

Core i7 8700K, Asus maximus code X mobo, 32gb ram windows 10 64bit  MSI GTX1080Ti GPU

I play VR mostly in Elite Dangerous, within the last 2 weeks (before the september update) the game has started flickering - the edges of objects going slightly more fuzzy at  every few seconds. AT first I thought is was a flickering due to changing in brightness  but it's also the edges of object going fuzzy. Rolling back nvidia drivers, reducing  the resolution in game, changing the wireless mode has no effect. Going back to a wired connection  stops the flicker. The latency is the same for both wired and  wireless and is dependent on the resolution set in game - VR low, medium, high and ultra. I'm powering the HMD with a usb 3.0 usb adapter plug not the battery when plying a seated game.

Any solutions or ideas would be welcome - I don't want to go back to wired even with a seated game.

Martin