In November 1811, by then BD, D'Oyly was appointed Hulsean Christian advocate, and in that capacity attacked
Sir William Drummond's theistic work
Œdipus Judaicus in
Letters to Sir William Drummond and ''Remarks on Sir William Drummond's Œdipus Judaicus
(1813). During his time at Cambridge he was a contributor to the Quarterly Review'' (some of his articles are mentioned in the memoir by his son prefixed to an edition of D'Oyly's sermons). D'Oyly also published: •
Two Discourses preached before the University of Cambridge on the Doctrine of a Particular Providence and Modern Unitarianism (1812); • an annotated bible, prepared with
Richard Mant for the
Society for Promoting Christian Knowledge ("D'Oyly and Mant's Bible") (1st edition, 1814, &c.; 2nd edition, 1817; 3rd edition, 1818); •
Life of Archbishop Sancroft, 2 vols. 1821; •
Sermons, chiefly doctrinal, with notes, 1827. His sermons delivered at St. Mary's, Lambeth, were published in 1847 in two volumes, with a memoir by his son, C. J. D'Oyly. Some of his sermons and letters on ecclesiastical subjects were published separately. His letter against the secular system of education of
London University addressed to
Sir Robert Peel, and signed "Christianus", was recognised in a resolution of the council of King's College, London (13 February 1846) as "giving the first impulse and direction to public opinion", making D'Oyly "virtually the founder of the college". ==Family==