Troubleshooting problem with file numbering display

[Budgie]

Hi Simon and many thanks for helping with this. A couple of preliminary questions:-

It is likely I made a mistake by adopting ID3v2.4 as I had forgotten there had difficulties with this when I rebuilt the machine. Which version should I use and do you suggest I change or work with existing setup?

I shall try using ssh so I can run the commands on the data in the NAS and let you know results.