Some background on Wallis Darlington & Matilda Adams:
Wallace Darlington [later known as Wallis] was born on 8th March 1884 in 89 Cork Street, Dublin son of James Darlington Compositor and Ellen Cochrane. His mother registered his birth on 18th March 1884 [Dublin South 1884 Group ID 9521316
https://bit.ly/2GBFhNa]; in 1901, Wallace Darlington was living with his parents and three siblings. He was aged 17, single, born Dublin, Engine Fitters Apprentice, Church of Ireland, living in 2 Spence’s Terrace, Dublin [1901 Census
http://bit.ly/2fr7nPF]. He married Matilda Jane Adams on 14th September 1908 in St Jude's CoI Parish church, Dublin [Dublin South Group iD 1879743
http://bit.ly/2z4jYUs]; Wallis was aged 24, bachelor, engine fitter, 2 Spence's Terrace, Cork Street, son of James Darlington compositor. Matilda Jane was aged 21, spinster, office clerk, 3 Tyrconnell street, Inchicore, daughter of William Stokes Adams, coach painter. The witnesses were James Darlington and M. Callander, celebrant Rev H McVitie Taylor.
Matilda Jane Adams was born 20th July 1885 in Crosbie Row, Limerick, daughter of William Adams, coach painter and Mary Jane Kane [Limerick 1885 ID 9706364
https://bit.ly/3DkFH9j].
In 1911 Wallis Darlington and his wife Matilda were living in house 16 Tyrconnell Street, Kilmainham, with their daughter Charlotte. Wallis was aged 27, CoI, born Dublin City, engine fitter, married two years with one child; Matilda was aged 23, CoI, born Co Limerick; Charlotte was aged 1 year [1911 Census
http://bit.ly/2zMfj6E]; Charlotte died on 9th August 1911 in Cork st Hospital from scarlatina, She was aged 1, daughter of an engine fitter, residing in Inchicore [Dublin South 1911 Group ID5191427
https://bit.ly/2MXEkqg]. Wallis died on 18th May 1945 in 24 Emmet Road, Inchicore, from VDH & DAH? auricular fibrillation & cardiac failure. He was married, aged 61, a fitter. His son Ralph Darlington of the same address registered his death on 19th May 1945. He was buried in Mount Jerome Cemetery, Dublin on 19th May 1945 [Dublin South 1945 Group ID 2553324
http://bit.ly/2i1OvXY & Death notice Dublin Evening Mail 18 May 1945 p1]. Matilda Jane Darlington nee Adams died on 30th July 1957 in St Anne’s Hospital [residence 24 Emmet Road, Kilmainham]. She was a 70 years old widow, cause of death carcinoma of the urethra and post operative shock. Her death was registered by Patrick Byrne, St Anne’s Hospital who was present at her death [Dublin South 1957 Group ID 2197852
http://bit.ly/2jnCL6g; Irish Independent 31 July 1957 p1]
Wallis and Matilda had the following children:
Mary Charlotte Darlington 1909-1911
Ralph Darlington 1912-1989 m. Elizabeth Kavanagh
Wallace Victor Darlington 1918 [b. Dublin, father a soldier/engineer]
Emmeline Darlington b. 1920
Phyllis Darlington
Nellie Darlington m. Joseph P. Murphy
Patricia Darlington
Since Wallis was away at war in 1916, I suspect that his wife Matilda had a liaison with Patrick Walsh? which resulted in the twins born in Liverpool & being registered as children of her husband Wallis. The 'scandal' was covered up when the twins were brought back to Dublin and baptised under the Walsh name.