Hi
Marriages prior to 1.7.1837 do not show fathers names - mothers names are never shown on English marriage certs
If the marriage cannot be found - a copy of one of their childrens birth certs will give you Elizabeth's maiden name
Births March qtr 1839
Harriet Taylor Crediton 10 78
Births June qtr 1842
Emily Taylor Crediton 10 70
until their last William Thomas b there Oct 1849
1851 shows William Taylor aged 5 so birthyear 1845/46