Virgin HUB 5 suddenly appears to be blocking Ring Doorbell and PodPoint charger?

Sorry for the vague title, but I don't really know what the issue is and it's driving me mad! I've had the HUB 5 with 1 additional 'Pod' and it's been fantastic, no issues at all. Then all of a sudden this week something changed that has interfered with some of my WiFi connected devices. Problem is I don't know what has changed or how to fix it...

I still have WiFi access and ethernet access on all my devices, so it is not a connectivity problem, but some of the devices are now malfunctioning. For example my Ring Doorbell shows a strong wifi signal, but will not connect to live view, will not record motion alerts to the cloud, and will not send doorbell push notifications - but it is connected to WiFi and the hourly 'snapshot' image IS uploaded to the cloud.

Similarly with my PodPoint, scheduling is no longer working and the app insists the Podpoint is not connected to the internet and can't communicate with it, and forces me into WiFi setup mode. But when I do the setup on the PodPoint itself confirms it is connected to the internet - PodPoint support also confirm they can see it is connected to the network. So it is not a connection problem, it's like Virgin is suddenly blocking part of the signal getting through...

I've tried searching for answers but I can't find any, there is another user that says they've lost access to 'Slack' since Monday on their HUB 5, I've no idea what that is but that's about the same time my connections went wonky...

It feels like Virgin have done a config change to block a port or apply a VPN or something that is causing connection issues, but I don't know what. So any technical help would be very welcome...

I've tried resetting the router, I've tried setting up a guest wifi and connecting to that, I've tried resetting and reinstalling all the apps of the affected WiFi devices, but nothing is working. The config menu of the HUB 5 is very limited so there isn't really much I can try. I tried disabling the 'Smart' feature for the WiFi management but that didn't work either. Something must have changed at the Virgin end this week - is there a way to know what?

Additionally I tried the network diagnostic in the config menu and that unhelpfully said 'Your home network has a few problems' but with no explanation what those problems were or how they can be fix... The VM Connect app is also showing 'Unknown' for all the connections and 'can't calculate device's health' so that is no use to me either...

Any ideas? I'm willing to try anything (short of having to buy a new router!)