@Alexandre. Hi, I have now carried out your test but there was no change to the other Ethernet connected Deco. Looking this morning, the X55 Deco in question now has an Ethernet backhual connection....

@Alexandre. Thanks for the reply. We have a very sensitive house guest at present who is working from home so I will try the experiment you requested when they have left and report back.

I have a mixed Deco mesh 3 x X55 and 1 x E4R. One X55 is the main Deco in the Study with other X55 in the Lounge and the E4R in the Integral Garage. There are ethernet backhauls from Study to Lounge...