There is nothing wrong with the incoming VM service. The 2G wifi still works while the 5G does not. I can be standing next to the superhub and the 5G still does not work. Once that happens, I can switch to 2G and I will get connection to the internet, if I switch back to 5G, the internet will stop. This is all while I am in the same room and have a clear sight to the superhub.
I think there must be a fault with the superhub2 itself.
Have you tried changing the 5GHz channel? I know5GHz is less prone to "interference" but at least it must be worth a shot. Run a wifi analyser app on the iPhone - I actually use the WiFi Utility that has a scan option you can activate. Then hit "scan now" at top right and in real time it will display all of the wifi networks in range and their channel numbers and strengths - do you see your own 5Ghz one disappearing ? I have an SH2 as well but it has always been in modem mode with an Airport Extreme sorting the wifi for me. You could always try that with your own wifi router. Or perhaps lobby VM to replace the SH2 for a Hub3!
-------------------- Services: HD TV on VIP (+ Sky Sports & Movies & BT sport), x3 V6 boxes (1 wired 2 WiFi,) SH2 in modem mode with Airport Extreme Router. On VIVID200, Talk Anytime Phone, x2 Mobile SIM only iPhones.