I posted earlier and a very helpful chap called Scott replied. Just wanted to say thank you - you mentioned deleting the network log so I went back to edit the post to do that and then lost your reply. But I’ve got the general gist (we need an engineer) and just spoken to VM who have booked one for us (obv not until Monday...). Anyway thanks for the help.
It shows the first line of my reply, but clicking the link just shows the original post, which does not appear to be linked to Fordybee's profile anymore.
Disclaimer - I don't work for Virgin Media. I'm just another VM user trying to help out. My setup: V6 TV box, Vivid 200 Optical fibre with Hub 3 in modem mode connected to a Netgear R7000 router. Telewest/VM user since 2001.