When I was in Dublin recently I spent some time at the Dublin Library looking up records. While looking in the various Trade Directories I came across some entries for Halpin/Halpen etc. but I did not search all the directories.
1761 The Dublin Dir.
Halfpenny Harrap, Tallow Chandler, Francis St.
Halfpenny John, Herald Painter, Britain St.
1776 Watson’s Almanack
Halfpen John, Herald Painter, 161 Britain St.
Halpen Richard, Wine Cooper, 44 Winetavern St.
Halpin Patrick, Engraver, 35 Temple Bar
1781 Watson’s
Halfpen Mary, Herald Painter, 161 Britain St.
(& Richd. & Patk. as above)
1790 Treble Almanack
Halpin Christopher, Grocer, 39 Old Church St.
“ Henry, Hatter, 24 Essex St.
“ Henry, Merchant, 24 Upper Ormond Quay
“ James, Grocer & Tobacconist, 13 Mary’s Lane
“ John, Comb Maker, 30 Greek St.
“ William, Tanner, 12 Kilmainham
Halpen John, Bookseller, 55 Henry St.
“ Samuel, Harness Maker, 64 Dirty Lane
1814 Treble Alm.
Halpin Mary & Martha, Haberdashers, 5 Mecklenburg St.
1861 Thom’s Dir.
Halpin Rev. Robt. C. , Chaplain to HRH the Duke of Cambridge & Chaplain to the Forces,
44 Manor St.
Two things to observe: John Halfpenny became Halfpen and his wife (or daughter?) had taken over in 1781.