For some time previously I had been using my Virgin Media hub 3 configured as a Modem with 3 Deco M5s set up in a mesh to provide WiFi. Fairly recently I started to lose the internet on a regular basis. The m5s were each  showing a red faulty light. The VM hub had a magenta light on ( as always). Unfortunately, I was unable to intergogate the hub as I understand I need a wired connection and I don't have a wired ethernet computer any more.
I have found out that if I reset the VM hub as a default router and the M5s as APs everything works with no loss of internet over that last couple of days!

The error log on the VM box shows a couple of "No Ranging Response received - T3 time-outs" but only one per day.

I've monitored the internet and the graphs look OK so to me it points towards the Decos.

Has anyone come across this before and/or could provide some guidance?

thanks.