Hope this helps........
Patrick and Peter were effectively interchangeable in Scotland.
From the IGI
*Patrick CARROLL, b 18 Dec 1856, Central District, Glasgow, Lanarkshire, parents Patrick CARROLL & Jane FLANAGAN
*John CARROL, b 22 Feb 1859, Blythswood, Glasgow,Lanarkshire, parents Peter CARROL & Jane FLANNIGAN
1871 census
Registration District 644/5 Clyde, Civil Parish Glasgow St Enochs, Enumeration District 30, Page 6
52 Maxwell Street
Peter CARL, 50, Head, Labourer, b Ireland
Elizabeth CARL, 23, Daughter, Millworker, b Ireland
Helen CARL, 17, Daughter, Millworker, b Cookbury Lanarkshire
Peter CARL, 14, Son, Painter, b Glasgow Lanarkshire
John CARL, 12, Son, b Glasgow Lanarkshire
Helen CROSSAN, 4 months, Granddaughter, b Glasgow Lanarkshire
From the IGI
*John CROSSAN m Elizabeth CARROL, 14 Jul 1865, High Church, Glasgow Lanarkshire
*Jane CROSSAN, b 6 Jun 1866, Central District, Glasgow Lanarkshire, parents John CROSSAN & Elisabeth CARROLL
*Elisabeth CROSSAN, b 18 Nov 1868, Hutchesontown, Glasgow Lanarkshire, parents John CROSSAN & Elisabeth CARROLL
*Helen CROSSAN, b 26 Oct 1870, Clyde, Glasgow Lanarkshire, parents John CROSSAN & Elizabeth CARROL
1881 census
Registration District 644/7 Blythswood, Civil Parish Glasgow St. George, Enumeration District 22, Page 19
5 West College Street
Peter CARROL, 60, Head, General Labourer, b Ireland
Elizabeth CARROL, 28, Daughter, b Ireland
Peter CARROL, 22, Son, General Labourer, b Glasgow Lanarkshire
Ellen CROSSAN, 10, Granddaughter, Scholar, b Glasgow Lanarkshire
Patrick MCMAHON, 6, Grandson, b Glasgow Lanarkshire
Lizzie MCMAHON, 4, Granddaughter, b Glasgow Lanarkshire
Re the new information re Patrick having re-married.
...
1871 census
81 Stirling St, Milton, Glasgow Barony LKS
Susan WELLS, Head, 33, Employed, b Coombes LKS
Charles WELLS, Son, 15, Master Apprentices, b Glasgow LKS
Susan WELLS, Daughter, 12, b Glasgow LKS
William WELLS, Son, 6, b Glasgow LKS
Mary WELLS, Daughter, 4, b Glasgow LKS
Rose MCDADE, 70, Mother, b Ireland
Mary MCDADE, 12, b Ireland
And Susan is in the 1881 census still under WELLS