Helen, I ended up believing you have not found the right marriage as her name was more likely Slop
Joseph married an Elisabeth Slop not Sloss
the clue in the 1841 census showing in the old Cumnock village
Elisabeth Slop b 1796 Ayrshire, living with
Mary Slop b 1821 Ayrshire
Elisabeth Slop b 1826 Ayrshire
George b 1828 Ayrshire
Helen b 1831 Ayrshire
the above Mary Slopaged 40 unmarried is visiting in 1861 her brother-in-law Joseph Chambers home in New Cumnock where the family is
Joseph Chambers38
Elisabeth Chambers 33
children
Helen 1851
Janet 1856
Nicholas 1858
Joseph jun b 1861
also
Mary Slop Sister-in-law
other research included
http://freepages.genealogy.rootsweb.ancestry.com/~rosdavies/SURNAMES/C/Chambers.htm has details going further back
for Joseph
Joseph CHAMBERS . Annahilt of Clintough; will dated 1767 & lodged 1778 IIW V4 p24
Joseph CHAMBERS . Annahilt of Clintough; will probated 1812 IIW V4 p24
Joseph CHAMBERS . Annahilt of Clintough; family burying ground in Loughaghery Presbyterian graveyard c, 1900 MIs
Joseph CHAMBERS . Annahilt son of Hugh Chambers; married Mary Harvey 11 Mar 1853 ; father of James b. 25 Nov 1867 & Robert b. 10 May 1871
two census substitutes give substance to Cluntagh townland
1. Tithes Applotment Books 1823-1837 based upon the work of the
Irish Genealogy Hub see
http://www.irishgenealogyhub.com/down/tithe-applotment-books/annahilt-parish.php#.WNaGsRicYwQ The relevant original books are in the
Public Record Office of Northern Ireland (PRONI) Belfast
Chambers, H. Townland: Cluntagh Year: 1829
Chambers, J. Townland: Cluntagh Year: 1829
Notes: John
Chambers, Saml. Townland: Cluntagh Year: 1829
Ros Davies also gives
Clintagh Clintaugh Clintough Annahilt 20: 30/54 see Cluntagh
2. Griffiths valuation there are 4 possible connections
Chambers William Magheraconluce Annahilt Down
Chambers Samuel Cluntagh Annahilt Down
Chambers Joseph Cluntagh Annahilt Down
Chambers Hugh Cluntagh Annahilt Down
her townland map shows Magheraconluce sits on the nw boundary of Cluntagh so close as likely relatives at some time
Loughaghery Presbyterian graveyard is covered by Ros Davies who offers a free gravestone look up but I notice there isn’t a burial book
Loughaghery Presbyterian Church in Cluntagh/ Cargygray townland- just south of Loughaghrey Road,Hillsborough Co. Down BT26 6DB; phone is listed
Baptisms from 1801 , marriages from 1830, graveyard attached, gravestone inscriptions UHF Vol 18; oldest stone 1807; email me Ros Davies for a gravestone look-upPRONI online church guide gives moreP. Loughaghery
Baptisms, 1801-1939; marriages, 1801-1955; marriage notices, 1889-1901; burials, 1868-1917; session minutes, 1801-96; committee minutes, 1909-35; weekly collection and other accounts, 1801-45; sacrament accounts, 1806-59; lists of communicants, 1824-60; transfer certificates, 1808-42. plus microfiche numbers etc
did you try Gretna Green records
Genes Reunited gives an Elizabeth Sloss b 1824 ireland in a tree
Genes Reunited gives a Joseph CHAMBERS b 1821 being a married man but living as Foundry labourer in digs b ireland in Rose Street Front, Govan Lanarkshire
in the 1861 census
a George was 12r old House boy in 1861 census in Old Cumnock for the big farmer John Craig No mention of other chambers
then I stumbled uponthe start of this note
Good luck onwards