I joined now tv on a £9.99/month using my smartphone but failed to get it running on a 2018 LG smart TV so I now need a NOW box but don't know how
If your LG Smart TV has the inbuilt native NOW App then you should be able to sign in with your existing NOW Membership that you use on your smartphone.
Have you tried clicking on the gear wheel icon top right of the NOW App on your LG Smart TV and then sign in with the same login details you use on your smartphone.
If that doesn't work is there any error message or error code when trying to watch on the LG Smart TV or do you see something like a QR scan code?
Forgot to add that NOW don't sell the NOW boxes or NOW Sticks anymore.
So look at something like a Roku streamer or Amazon Fire Stick.
Hopefully if your LG Smart TV has the NOW App from the TV Apps Store you should be able to watch from that instead of buying an extra device.
I’m mystified why you can’t get it running on a smart 2018 LG TV.
Press Home, scroll along the horizontal row of icons until you come to the little pink shopping bag icon, the LG Content Store, go to the magnifying glass top left, and type Now. Highlight it, press OK on it.
If it appears, scroll to top right, click the gear wheel, sign in.
If all OK, pick the membership you have on the left, and Start Watching.