Have you seen this yet?
Clotworthy Dobbin Devitt on list of Insolvent Debtors (Perry's Bankrupt and Insolvent Gazette (London), 23 Oct.1828)- St. George's St. Dublin, spirit-dealer, trading under Thomas Devitt & Co.
and
The Bristol Mercury (Bristol), 7 July 1832: petition from Clotworthy Dobbin Devitt asking for redress regarding sudden dismissal from General Post Office without any reason being assigned and an inquiry into frauds in post office also mentioned.
and
The Standard (London), 20 August 1839: Clotworthy Dobbin Devitt late a clerk in the General Post Office, Ireland (there 17 years before 1830), now of Birmingham "gentleman"... long, long article which I have not attempted to thoroughly read