James Cowin in 1902 but speaking personally of events of his boyhood - the great spud riot (?1840's) speaks of Gutter-a-gable as close to Norris Clague's shop at devil's elbow in Strand street who by cornering the market for potatoes in a time of great scarcity provoked a serious riot - also uses same name in an 1899 article which seems to imply that the alley way was rather insalubrious
Kneen dates name from 1832 in Manx Sun

There was a Robt Guttery (+ dau jane + Guttery's garden ) in Ramsey c. 1710-1740 but nothing I can find in Douglas