Try "googling" - I came up with just a few as follows (you don't give full names, so used surname Cowen/Cowin only in my search).

1790 Gore Directory – Liverpool
Cowen , Capt. John, 77, Sparling st.
- and -
Liverpool Pole Book 1832
COWAN,ISAAC,BRICKLAYER,St.THOMAS' BUILDINGS,LIVERPOOL,S & D,
COWAN,ROBERT,GROCER,MARYBONE,LIVERPOOL,S & D,
COWAN,SAMUEL,DRAPER,PETER LANE,LIVERPOOL,E & T,
COWEN,HUGH,JOINER,BLUNDELL STREET,LIVERPOOL,S & D,BGS/FMN

Hope this helps.