I have had a BT Whole system for several months and other than a slight Sonos glitch it has been working amazingly. Last week I purchased a Netgear Gs724 managed switch, since installing this I have had no end of issues. My setup is two discs are connected to the switch via ethernet, with the third connected using the 5ghz backhaul.
It would seem that once the two Ethernet devices are connected to the switch the network separates, only one of the Ethernet connected devices visible in the app. I have done the obvious steps to sort it, with no luck.
As a stop gap I have connected the two discs together on a unmanaged switch, but ideally I would like them both using the managed switch.