Sorry to hear of your problems Jez.
My experience is it doesn't get any better. Had intermittent internet for two and a half months now. Last week after a bit of an argument because I wouldn't just accept £10 compensation, the manager agreed to send an engineer on Saturday. The guy changed the hub saying it was faulty and asked me to check on my phone for wifi. Before I could turn my phone on, let alone put new router details in, he was on his way out the front door. He had already told me the engineer booked had a vm Xmas party to get ready for.
Contacted vm again this evening as issues have persisted. I already knew vm had closed my case without contacting me. I asked why and was told manager did try to call me but didn't get an answer. I hadn't had any missed calls, plus he could have messaged or emailed me.
Apparently one attempt to contact is a good enough reason to close the case.
Now the usual response there are outages in your area and are due to be fixed by 13th. They didn't state which month or year so are covered I guess.