Can someone advise where I may locate service records for a soldier who served abt. 1855 to 1867, in St. Helena Island

Thomas Easterby HUTCHINSON, born 1837/1838 in Lightcleiffe, Yorkshire, England, while in St. Helena married Elizabeth Martha ELLIS in 1858, ( she was born in St. Helena in 1843) they had 4 children in St. Helena, and returned to England, abt 1867 and had 2 more children, in 1871 they sailed to Canada.