I am looking for a Martha Wallwork, born in Oldham, Lancashire around 1823, married John Clapham at St. Chad's, Rochdale, Lancashire on 26 Feb. 1844.
In looking through the 1861 census, I found this:
Elizabeth Wallack, head, mar, 60, housekeeper, b. Cumberland
Hannah Casper, dau, mar, 27, b. Jamaica (British Subject)
Frederick Casper, son, 7, b. Oldham, Lanc
Hannah Casper, dau, 5, b. Oldham
Christopher Casper, son, 2, b. Oldham
Charles Casper, son, 7 mos., b. Oldham
Thomas Wallack, son, mar, 24, cotton spinner, b. Oldham
Sarah Ann Wallack, dau, mar, 23
Charles Wallack, son, 1, b. Oldham
James Wallack, son, 19, b. Oldham, engine fire stoker at a cotton mill
They were living at Raymers Buildings, Oldham Below Town, Oldham, Lancs.
The name Wallack, I strongly believe, is actually Wallwork. (Thomas and wife Sarah Ann and sonCharles all show up in 1871 as Wallwork, as does James).
The LDS website has records of Hannah Elizabeth Casper chr. 11 Aug 1856 and Christian Casper chr. 24 Jun 1858. This would appear to match the Hannah and Christopher in the 1861 census.
I expect that Christian and Margaret were away for some reason during the census and left their children with their relatives.
Casper does not appear to be a very common name in England. If you can find an earlier census, you may get some more answers.