I am a descendant of William Barber of York (town) who obtained land in Gwillimbury ( 1819/1820) through his service as quartermaster sergeant in the militia in the 'late war'. He married in York in 1810 and was the clerk and gaelor in York for several years. He became a teacher, and tavern keeper in Newmarket, dying before 1848. There is a lot of differences with the person you are interested in. Is this the same person? I counted 22 land petitions for William Barber between 1806 and the 1850s.