Hi Joan,
Had a bit of luck found Elizabeth's surname by finding their son John WOOD who had moved back to Somerset - 1881 he is living in Honeysuckle Alley Bridgwater Somerset same place as in 1851.
What a stroke of luck he's living with his grandmother who is Elizabeth
PITMAN RG11/2374/128/20.
Curious though there's an entry for Elizabeth WOOD b1827
Wedmore, Somerset
married, mariner's wife with dau. Emily b1867 Bridgwater, Somerset living Honeysuckle Alley Bridgwater - RG11 /2374 /129/ 21
On 1871c Glamorgan Wales Elizabeth is widowed, born Bridgwater, Somerset is the above 1881c entry just a co-incidence?

Charles (CHAS.) WOOD he's living in 1881 Cardiff, Glamorgan at the same place as in 1871 - RG11 / 5278 / 76/ 33