Thank you very much for trying to help, I have all the wifi calling etc turned on temporarily whilst I have zero network coverage however the phone is constantly seeking a signal so tries to take the call through the mobile network route rather than wifi. It won’t even send or receive a text message through wifi, even though the network signal signal is well and truly dead. I can send and receive calls through What’s App with excellent quality (better than 4G when the phone case is fitted) but I can’t call Virgin on What’s App or change my password so I can log into Virgin Mobile to report the problem (can only be done using a text message - played that game before 😳)
It is really strange as I have never had a network problem in the 9 years I’ve lived here and have a 10 month old enormous 5G mast about 80 yards from my front door, with no disruption of line of sight.
I have a sneaking suspicion it’s one of those apple own-goals where they update the IOS and create some awful bug with the network connection settings, it may miraculously but silently resolve itself in 2 updates from now following strenuous denials from Apple that there was anything amiss.