We changed to NowTV only a couple of months ago. Suddenly, a week or so ago, we lost access to all ITV Hub programs & box sets. The main problem gave screen message "unable to access this channel at this location". I tried changing my location in Settings but nothing helped. After hours of trial & error efforts over the xmas period I've managed to resolve this problem.
I eventually decided to turn all hardware off. The TV, router & unplugged the NowTV stick. First step: turn on tv. Second: power up the router & wait for it to finish booting up. Go to TV settings & make sure that the tv internet connection is set to cable / ethernet NOT WIRELESS! Once connected plug in NOW TV stick / box & turn it's power on. After this step I have been able to watch all ITV channels & box sets etc on the ITV Hub with no problems. I don't know if this fix will work for everyone with a similar problem, but fingers crossed it just might.
Merry Xmas & Happy New Year
