This is a weird one which is driving me mad!
I had an old Pioneer 428xd plasma and had compatibility issues when I upgraded to the 360 box, the Virgin engineer could only get it to work if we selected 1080i rather than 1080p, he suspected either TV or cable issues. I've now upgraded the TV to a LG G2 bought from John Lewis, the installers couldn't get any decent picture from the virgin box, only through the freeview aerial signal and said I needed a proper TV engineer to resolve the problem.
I should say I have the 360 box and Pioneer blu Ray player connected to a Pioneer receiver SC 1224, and then by a pretty long (apprx 5m) hdmi cable to the TV on the wall.
I've now managed to get the LG working through the 360 if I turn everything on in the order TV, 360, receiver but with a few flickering issues, sometimes a blackout and sometimes some colouration in the top left of the screen. Tonight though the flickering issues were terrible, so I played a blu ray instead which worked perfectly. When I switched the receiver back to the 360 input it also worked perfectly and is still OK.
Does anyone have any idea what is going on here and if I need specialist technical help to resolve the problems?