iPhone XR no longer showing caller id

Quick update. This seems to be the consequence of a formatting issue with contact numbers, which despite dial assist AND ensuring the region and language settings are correct, was inserting spaces between numbers. I had to go into each and every contact number and add the +44 prefix for the UK. Prior to manually updating I noticed that for the last few days incoming calls that had lost their correct format were prefixed with +32 Belgium!! Threads elsewhere have picked up on this issue although no one, including my network provider seems to have a clue as to why this suddenly happened. While I implied that switching off dial assist might be the origin, this can not be the case. Any info much appreciated even if I have resolved for now.

Ok, sadly, this has not permanently fixed things. After reformatting the numbers things ok for a few days then back to 'call failed' notices. Interestingly though, if I go through messages, select info for sender/contact and then select audio call, the calls do not fail. So, calls failing when selecting from 'contacts' or 'recents'. By example the formatting I use is +44 (0) etc etc, with the language and region set correctly and with dial assist off - working ok then can only make call by either reformatting number to drop +44 (0) or switching dial assist ON. Go figure. Initially reformatted to deal with the spacing issue of contact numbers. Also. need to mention that for no reason whatsoever, all of a sudden numbers prefixed with +44 were reassigned +32 for Belgium! Have tried everything, reboot, reset network settings, toggle airplane mode and soft reboot, software updates, dial assist on/off, etc etc etc. Any thoughts please before I lose complete faith in Apple.