This paper charts the early history of the accordion in Scotland:
Stuart Eydmann, ‘As Common as Blackberries: The First Hundred Years of the Accordion in Scotland, 1830-1930.’ in Folk Music Journal Vol. 7, No. 5 (1999), pp. 595-608 can be read here.
The subsequent story of the instrument is covered in this paper:
Stuart Eydmann, ‘From the “Wee Melodeon” to the “Big Box”: the Accordion in Scotland since 1945.’ in Malcolm Miller (ed.), ‘The Accordion in all its Guises’. Musical Performance Vol. 3, Parts 2-4 (2001), pp. 107-125 can be read here.