Thanks for your reply On both TVs we have the TV v6 box.
The video output is 2160 and this was automatically detected as the best setting.
I've moved the Hdmi cable on your advice.
The thing is, the picture isn't terrible, it's just a bit lifeless ....as in not very vivid in comparison to the TV in the other room. Most noticeable on football matches where the pitch looks pale......almost as if its slightly foggy. Sorry for my lack of technical knowledge!
If I click on the Samsung TV app and watch something through that, the colours are brilliant which made me think it must be the Virgin box.....but again I may be wrong as I'm not technically gifted with tvs to say the least.
Thanks again for your help