4G has stopped working

I had seen that, but it’s said the same thing for weeks now, so it’s not the most helpful.

I agree with you, my area has been showing that same result on and off for several months and its not the best in giving out any useful info, but that’s all we have to go by from 3UK (and thus iD). The only other thing to consider it that for your postcode the 4G is claiming to be good indoors and outdoors, whereas 3G is only showing as good outdoors. Your phone might be bouncing between 3G and 4G (there is no 5G there).

I did contact ID through their Live Chat, but the agent was insistent that there is something wrong with my phone settings ….. which is not the case as lots of people are being affected in my area with the same issue.

They could well be thinking if you told him/her that your 4G stopped working completely that it may be a phone settings issue, as mine does work but sometimes it doesn’t. 

If your phone is sat there idle and you go into the settings then 4G should be showing. If there's nothing signal wise then your problem might even be something like a faulty SIM card. Or as I mentioned your phone could be moving between 3G and 4G too often (I get this too at times and I really should look at mine to force my phone to use 4G only).

A member of staff on here may be able to clarify in better detail than the above checker what is going off for your postcode. They have more detailed info available.