Hi there,
Can you let us know where you have him after 1892 (in terms of marriage, censuses, etc)?
All the info from his marriage, also - witnesses can be a great clue to birth family.
Was he still living in 1939? Knowing his birthday can help confirm whether earlier birth records are the right person, so finding him in the 1939 register could really help.
A possible line of inquiry:
There is a Thomas Blundell, aged 20, born Ince Blundell in 1881, living in the household of his aunt Elizabeth Lea:
https://www.familysearch.org/ark:/61903/1:1:Q27L-KM7Khttps://www.familysearch.org/ark:/61903/1:1:VBNN-Q1LIn 1871 Elizabeth she is with her parents Thomas and Ann Lea
And in 1861, there is an infant Thomas Lea with this family
https://www.familysearch.org/ark:/61903/1:1:M7YQ-1CCAs well as Elizabeth, they have a daughter Mary who could be the mother of this Thomas
There was a Thomas Lea, born West Derby district, Jun 1860 quarter, 8b/361 - illegitimate as no mother's maiden name - could this be
Mary Lea may have married Laurence Blundell in 1862 - it appears there is a Thomas, aged 10, with them in 1871 but not in 1881, where Laurence is widowed.
Perhaps he was born Lea, but raised in the household of Laurence and Mary Blundell, at least until Mary's passing? It's not uncommon in this case to find the child raised under the stepfather/(possible birth father)'s name. He may have reverted to Lea as an adult as that was the name on his birth certificate.