Just read something that said your TV's running Amazon's Fire OS, and since the Now TV app was just rolled out to Amazon devices today, and vice versa, I'm guessing the roll out for the TV OS will probably take a little longer.
You should be able to get the NowTV App on the JVC Fire 4K models (according to these two NowTV articles).
Ignore the 2K reference on the second link under Smart TV's where i am assuming it's a typo (unless JVC sell a 2K model).
Be patient and i would have thought the App will be available in the next 48 hours (maybe keep checking and doing a search under the JVC Apps Store).
Me neither. It’s very frustrating. I suggested a JVC Fire TV for my old man, and as a Now TV subscriber myself at home on my LG, was excited to hear he would be able to get access to all the great content. It’s still not there as of writing on 18/12/2020. It’s very poor to be honest. As a pensioner it would have made his Xmas to be able to watch the box sets and movies. I don’t know whether the blame lies with Now TV or JVC but it’s making me rethink my continued subscription. It really is shocking that in 2020 people are unable to watch what they want when they want.
What’s confusing is that the Sky cooperate announcement states “All other Fire devices” will be early 2021.
Whereas Now TV articles state it’s launched.