Can't find a marriage but there are these christening details from familysearch beta - may help in the search for the marriage
Christenings Berwick upon Tweed, Northumberland
Parents named as James HASWELL & Isabella
Elizabeth 21/8/1842
James 08/2/1846
John 5/7/1849
David 20/4/1851
Rosanna 24/9/1857
James Jordan 14/8/1859
Johnson Borthwick 26/8/1855
Isabel 6/10/1861
info. from familysearch beta
these christenings may be a different family
Isabella HARWELL 6/2/1848 parents named James & Isabella
Thomas HASWELL 19/3/1854 " "
this appears to be the family in 1851
1851 Chapel Street, Berwick Upon Tweed, Berwick
HASWELL, James Head Married M 28 1823 Cooper
Isabella Wife Married F 21 1830
Elisabeth Daughter F 8 1843 Sch
William Son M 7 1844 Scholar
James Son M 5 1846 Scholar
John Son M 1 1850
HASWELL, Elisabeth Widow F 67 1784
all born Berwick
same address 1861c plus 3 more children
David 10 1851 Rosanna 3 1858 Scholar James 1 1860
same adress again in 1871c plus two more children
Isabella 1863 Jane 1864
Chapel Street in 1881 James (Cooper), Isabella & Jane
Chapel Street in 1891 James (Cooper), Elizabeth ?) & son in law
1901 Berwick Upon Tweed Isabella Inmate Widow F 78 1823 Formerly Inmate Fish Cleaner Berwick upon Tweed