My wifes vivoactive 3 is constantly searching for Varia lights. It seem to reduce battery life and is annoying as we do not have any Varia lights. There is no Varia lights mention in Connect app or on watch setting. Turning watch on and off has been tried.

Why do you think that the watch is searching for Varia lights?

Have you checked in the sensor menu if there is a light configured?

I have checked the sensor menu both in the watch and in Connect, and no lights are mentioned. Very strange indeed. 

Try disabling the option Sensors & Accessories » Auto Discover and see whether it makes any difference.

On the clock the Sensor & Accessories menu contains Compass and Wrist pulse, but no Auto Discover.

What makes you think, that your watch searches for Varia lights?

On the screen of the watch: "Searching for Varia"

I have now reset the watch to factory setting, deleted the Connect app, reinstalled it. This is 24 hour ago and the message has not reappeared yet. Crossing my fingers.