@pixelart Thanks everyone for your replies.I finally got things working by reseting the main Deco unit with a pin. After running set up things started to work - I'm now getting 352 mbps.

I have been using the Deco M5 units now for over 18 months with one as a router connected to a Virgin Hub 3 in modem mode. Until last week I was using Virgins M100 mbps but have just upgraded to...