Working on the fact Sarah claimed Charles was still alive on April 5th, 1891, these are the deaths I've found which fit with an approximate birth year. I noticed 'Heywood' and 'GeoffE' both found likely birth registrations in 1851.
The 1881 claimed Charles was aged 27 years - therefore a death registration could have placed his birth year as late as 1854 if the informant wasn't entirely sure.
By process of elimination and not to say he's one of these because realistically he could be anywhere, at least it's a step in the right direction :
Death, Sep qtr 1893
Charles Harrison, age 39
Bolton, Vol 8c, page 369
Birth, c.1854
~~~~~~~~~~
Death, Sep qtr 1894
Charles Harrison, age 40
Islington, Vol 1b, page 142
Birth, c.1854
~~~~~~~~~~
Death, Dec qtr 1894
Charles Harrison, age 41
Warrington, Vol 8c, page 106
Birth, c.1853
~~~~~~~~~~
Death, Mar qtr 1895
Charles Harrison, age 42
Birmingham, Vol 6d, page 168
Birth, c.1853
~~~~~~~~~~
Death, Sep qtr 1895
Charles Harrison, age 43
Wharfedale, Vol 9a, page 99
Birth, c.1852
~~~~~~~~~~
Death, Mar qtr 1896
Charles Harrison, age 46
Edmonton, Vol 3a, page 158
Birth, c.1850
~~~~~~~~~~
Death, Jun qtr 1900
Charles Harrison, age 48
Bolton, Vol 8c, page 322
Birth, c.1852
~~~~~~~~~~
Death, Dec qtr 1901
Charles Harrison, age 47
Aston, Vol 6d, page 228
Birth, c.1854
~~~~~~~~~~
Death, Sep qtr 1902
Charles Harrison, age 48
Christchurch, Vol 2b, page 386
Birth, c.1854
~~~~~~~~~~
Death, Mar qtr 1903
Charles Harrison, age 47
Wakefield, Vol 9c, page 47
Birth, c.1856
~~~~~~~~~~
Death, Jun qtr 1903
Charles Harrison, age 52
Bucklow, Vol 8a, page 118
Birth, c.1851
~~~~~~~~~~
Death, Mar qtr 1904
Charles Harrison, age 53
Plymouth, Vol 5b, page 180
Birth, c.1851
~~~~~~~~~~
I'm also wondering why Sarah and Thomas Harrison are claiming to be man and wife in 1901 - but didn't marry until 1904. Did they have to wait until they'd heard that Charles Harrison had died, meaning a death between 1901 and 1904. Or had Sarah been 'deserted' for sufficient enough years to enable them to get married.
Hope to goodness my sums are right because it's getting fairly late here.
Pels.