Thanks again for your reply. I have watched the YouTube video now. Firstly the video-makers Viera is a much newer model than mine but the update procedure is almost identical. I had upgraded to the newest software available before I had even started this thread so now I'm just stuck with old software that doesn't work and can't be upgraded.
It's interesting that the video maker with a much newer Viera than mine also had a less than brilliant upgrade experience.
I currently am having a similar experience with a 2 year old Huawei phone which is not being upgraded beyond Android 9 nor is their new (Harmony) operating system being offered. Its like other people have commented, big brand companies like Panasonic and Huawei have no interest in updating their products, they just want to consign usable equipment to land fill and buy the same thing again from them, and end up with the same problem in a few years time - shame on them 😡😡 Don't do it folks!