It does not quite add up.. but anyway..
What model TC are you using?? A1xxx from the base please..
Reset it to factory..
Start from a factory reset. No files are lost on the hard disk doing this.
Factory reset universal
Power off the TC.. ie pull the power cord or power off at the wall.. wait 10sec.. hold in the reset button.. be gentle.. power on again still holding in reset.. and keep holding it in for another 10sec. You may need some help as it is hard to both hold in reset and apply power. It will show success by rapidly blinking the front led. Release the reset.. and wait a couple of min for the TC to reset and come back with factory settings. If the front LED doesn’t blink rapidly you missed it and simply try again. The reset is fairly fragile in these.. press it so you feel it just click and no more.. I have seen people bend the lever or even break it. I use a toothpick as tool.
N.B. None of your files on the hard disk of the TC are deleted.. this simply clears out the router settings of the TC.
Plug the WAN port of the TC into the LAN port of the virgin superhub.. and then plug the computer into LAN port of the TC..
Run the airport utility.. but warning the last version for windows is not suitable for the latest version TC. So if you have gen 5 TC.. tall one you should use a Mac or iphone/ipad with iOS version airport utility.
Run through the setup utility and put the TC in bridge mode.
The stuff in the article about DMZ is not going to work.. so ignore all that.
If you setup bridge the virgin superhub will work as the main router and you can even leave its wireless on.. there is no need to turn it off.. in fact in bridge for the TC the guest network is off.. so the superhub can work as a secondary guest wireless.. just use a different wireless name for the TC. I recommend all names that are short, no spaces and pure alphanumeric.. this is simply good network practice.