I can now complete the story of the marriage at the head of this thread.
Herbert was born on October 3rd 1874 in Marylebone, London to George and Harriet West.
He married Ellen Elizabeth Liquorish in London on August 21st 1898 (Note 1: a Weslayan Chapel). The pair were living in Fernhead Road, London in 1901.
Obfuscation 1: Ellen Elizabeth had returned to her parents' home in Cottingham, Northamptonshire at the time of the 1911 census - alone and suspected abandoned by Herbert. This led to the Ancestry assumption that Herbert had moved the Birmingham area.
Herbert was employed by the railways all his working life - first by Great Western and then by Central London. Employment records show that he retired in October 1934.
Herbert had a half sister named Flora born in 1883. In December 1923, Flora married Robert Edward Liquorish at the Register Office, Ashby de la Zouche, Leicestershire. Robert was Ellen Elizabeth's younger (by five years) brother. His first wife, Sarah Elizabeth Harrison had died of Hodgkin's lymphoma in 1921.
The proof:
Herbert West married Nellie Searle at the Belvoir Road Methodist Chapel, Coalville, Leicestershire on November 3rd 1934. Both described themselves as widower and widow. Nellie had married Thomas George Searle in Paddington, London in 1906. The ceremony was witnessed by R Liquorish (Ellen's brother) and F Liquorish (his wife). After that, the couple moved to Cardiff. Herbert died there in 1942.
Well, where was Ellen Elizabeth after 1911? Well, the time frame 1911 to 1934 pointed to a possible death occurring in the Hendon District in London in the early months of 1931. Following up on that, The Electoral Registers for England & Wales show that Herbert and Ellen E West were living at 81 Thurlby Road, Wembley London.
So, that answers my main question with a negative: Herbert West was not a bigamist!
Cheers Alan