They had a son who was called Giles Rowland Durham, born 1857, died 1861. Which, with reference to the 1850 marriage, seems to point to a Jane Rowland being the wife of William Durham!
Baptism at Hannington, 2 September 1827
Giles Rowland
parents James + Mary
1841 possibility
piece 1178 book 8 folio 15 page 8
Parish - Hannington
James Rowland Ag Lab 55, Yes (born in county)
Mary Rowland 50 Yes
Jane Rowland 10 Yes
Odd, an Elizabeth Rowland was baptized at Hannington, 6 August 1830, parents James and Mary. Not Jane!
Giles Rowland was away from home in 1841, is back with his widowed mother Mary in Hannington in 1851 (piece 1833 folio 174 page 9). No sign Jane