I found the Pentlands to be more elusive than other sides of my family - there never seem to be many marriage certificates or appearances in the census. My dad wonders if they didn't just adopt the name at some point!
Your dad may be right!
This is likely the family in 1871 from what we have:
William Templeton 30 Labourer Iron Work b. Ireland
Elizabeth Templeton 40 b. Ireland
Joseph Templeton 14 Catcher At Rolls b. Coatbridge, Lanarkshire
William John Templeton 8 b. Coatbridge, Lanarkshire
Elizabeth Templeton 4 b. Coatbridge, Lanarkshire
Address: Depot Canal Bank Reid Land No 8, Coatbridge
Monica