I'm sure Blairgowrie had quite a large Fiddle & Accordion club at one time, some of those players might still be about, and worth asking if any of them have memories of your granda. Unfortunately, Tommy Newcomen closed his music shop - not sure if he's still around Blair or not, but he would have known most of the players on that scene. Could be worth trying to track him down.
Accordion player Gordon Patullo in Coupar Angus is someone else who might be worth contacting.
This doesn't help with your initial request, but you seem to have managed to get at least some of the music you're looking for.
Good luck.