Hello Paul! When resetting the Eve Extend you have to reset all formerly attached Eve accessories first and add them again to the home in Eve or Home. Once done perform the reset on Eve Extend: https://help.evehome.com/hc/en-us/articles/360035315593-How-do-you-reset-Eve-Extend-
If this does not help, please open a ticket in https://www.evehome.com/en/support/ticket
Best regards, Volker
Dec 28, 2020