Sudden volume limit on ipod nano 3rd gen

I have had my ipod nano 3rd for several years now and up till saturday 7th dec the volume was fine, even at max it wasn't too loud, but it could go high enough so quieter music could be heard at decent volume.

On sunday I went to use it, and I was shocked to discover that even at max volume the music was far too low to be enjoyable, rendering the ipod useless to me.

Now I read about EU ipods having a limit set on them, but why did mine that has had the same decent volume for years suddenly lose about 40% volume just the other day?

It's not the volume limiter, that is set at 100%, and nothing I have tried can restore the volume to what it was just mere days ago.

I saw no mention of any update when using itunes recently, but have they made some change to the ipod software in last week?

Is there any solution to restore the volume to what it was, perhaps reset it to factory settings?