Hi John. The fact the dealership saw the problem and told you there is nothing they can do and for you to contact Hyundai UK and open a case with them is total bollards. The dealership should be the one opening a case with Hyundai rather than fobbing you off. If it were me I would be contacting motability.
also worth checking on here https://www.hyundai-forums.com/forums/?msclkid=34eabca3c22611ec9389c1491787ff7c
Are you sure the latest software was installed correctly or could it have had a bug in it. Ive seen tis mentioned on the above site.
I will tri POI and landmarks on mine today as not used them yet.