My issue seemed to be my 1.4 hdmi was connecting but my tv was making the v6 box only pick 2160 as the video output which my cable couldn't handle. When I used the virgin hdmi cable it let me go in to settings and select 1080 so I could quickly change back to original v1.4 hdmi cable. I have ordered a 5 metre hi speed v2.0 hdmi cable so hopefully that'll fix the problem more permanently.
I have a Samsung and upgraded to the V6 box. It was working for the first 3 weeks then the picture went but we still could see the menus and had sound. The 1st engineer said it wasn't compatible and to purchase another TV as it wasn't working. I took the TV to a local engineer who said the TV is in perfect working order and it was working on Freeview. Then we had 2nd engineer who said the same and downgraded the box to check and it still didn't work. I then spoke to the fault line who advised me to purchase a HDMI splitter. So off I went to a very well know store and explained the situation. They explained what a splitter would do and that certainly wouldn't help. They did suggest that VIRGIN have done some updates that are probably not compatible with certain TV's but would NEVER admit it! I would love to hear a response from VIRGIN on this matter after 2 Engineers and spending at least 3hrs being fobbed off on the phone and sent completely misguided information.