Griffith's Valuation has a Robert Mitchell at 168 Rathmines Road, Haroldscross East, in 1847 and 29 Rathmines Road, Haroldscross East, in 1850.
Thom's Directory 1851-52, has Robert Mitchell, confectioner, at number 68 Rathmines Road (Fortescue Terrace).
Is there a 1853 directory of Dublin?