Mine was doing the same. The time on my roku black box was behind by 1 hour.
If you go into the tv guide it will freeze as there's a clash in timings.
I went into setting and selected 'set the time manually' and selected Ireland as UK was showing as 1 hour behind. Problem fixed, tv guide working fine.
Think sky need to make an adjustment to the timings their end - until then this tweak fixed it for me
My Now TV box started playing up tonight. I’ve done the resets and system updates with no success however like a few others on the forum I have noticed that in the system setting the UK time is incorrect and is showing 1hour behind the actual time. I could not alter this manually however I have now selected Ireland as my time zone instead of the UK and my box is now working just fine! Obviously this is some sort of back ground software issue that needs to resolved by Now TV however this manual fix should get you back up and running in the meantime.