Your clue here was the name of the footballer, James Welsh of St. Johnstone - simply because St. Dwynwen was Welsh. Now I have had a hunt but I cannot find any other cards showing this footballer, and an online search seems to suggest this is his only cartophilic appearance.
We do know that he formerly played for Clydebank, and that he was the first signing for St. Johnstone by their new manager, former Rangers and Scotland international Tommy Muirhead. That was in 1931. James Welsh was then described as a defender, and almost apologised over with the following statement “Although small of stature, he is strongly built, a sure tackler and a powerful kicker”
He made almost two hundred and fifty appearances for St. Johnstone between 1931 and 1939, and saw them gain promotion to the Scottish First Division in his second year, 1932. They also reached the semi finals of the Scottish Cup in 1933-34, but they lost to Tommy Muirhead`s former team, Rangers.
As for St Johnstone Football Club, that is in Perth and it gets its name from St. John`s Toun, which was a former name of Perth. It was founded in 1884, and they played their first match the following year. However they did not join the Scottish Football League until 1911.
They are one of several football clubs whose nickname is "The Saints" - and because of this they are often also known as "The Perth Saints".
It is quite hard to find anything out about this set, but we do know that there was a special album issued, a rather grand one as well, and you can see it at the Football Cartophilic Information Exchange / Mitchell Snaps