Hi Judith,
There are actually a few George Wood entries for 1891 in Durham. I found them on Ancestry.
George Wood born abt 1856 Sunderland, living in Sunderland, Bishop Wearmouth
married to Margaret Jane age 28 born Sunderland, son William age 11 days born Sunderland
George Wood born abt 1855 Monkwearmouth, living in Willington
married to Mary Ann age 33 born Willington, children John 14, Henry 7, Elizabeth 5, George 3,
Thomas W 1, all born Willington
George Wood born abt 1856 Durham, living in Bacup Lancashire
married to Mary age 36 born Derbyshire, daughter Mary Ward 10 (definitely looks like Ward not Wood)
None of them match George's 1871 occupation of blacksmith.
Lesley