I am delighted to have just come across this forum. My grandfather, John Gauld Fullerton was the older brother of Alexander Craig Fullerton. John G, born in 1895, was the eldest of five, of whom the others were: James D (b abt 1900), Alexander Craig, Margaret B (b abt 1903) and Marion E (b abt 1906). John G married in 1920 and died in 1967. He was a commercial artist and lived in Jesmond, Newcastle-on-Tyne.
Did you ever find anything more about the bankruptcy?