Yeah, most carriers have an agreement with the WiFi service available in stations, but it's easier to get on the network with some carriers than others. When I was on EE, I could just authenticate through the Virgin Media portal, but with O2 I have to connect to 'WiFi Extra' and use my SIM as authentication.
Anyway, if you're connected to the WiFi and you have WiFi calling switched on, you should be able to make calls from underground. And it will show you as having some signal, though really it's just WiFi if that makes sense.
Wifi won't show up as coverage. It will show up as wifi just like when you connect to it at home. You have to connect to the Virgin wifi and authenticate through the captive portal. Even then, the wifi is only at stations, not on the trains or line itself, meaning when the train is moving between stations you won't get any wifi signal.
It's still rubbish though, some stations it's very unreliable due to congestion so I hardly bother with it any more.
I was wondering why I wasn't that impressed with the 700 headphones then I realised the Bose Music app was kicking the headphones into LE mode. Uninstalled the app, repaired the headphones and it sounds much better. I lose out on things like ANC and equaliser controls but I already have those set to my preferred settings before removing the app.
My Sony XMS3 earbuds was also coming up as LE after I paired the 700 so I wonder if it was somehow affecting it.
I saw an article that one plus has applied for a patent or something for a triple folding phone. Think folding phones will be back in style haha!! I hope not to be replacing the pixel 6pro for at least 2 or 3 years