ITV 2, 3, 4 and others not working.

Hi guys.

I'm a noob so hope someone can help me out. I know the Sly channels have gone now but I can't access any of the ITV HD channels and many other FTA channels other than the big 5. Does it have something to do with having to update DNS or something else I need to do (done this thanks to my provider who provided new link which I've performed on the box)? TIA