There is a Henry George Symondson listed in the April to June 1900 birth index, St George Hanover Square district volume 1a page 441.

Parish Records St. Gabriel, Warwick Square, Pimlico, Westminter, London
Born April 17 1900, baptism October 14 1900, Henry George Symondson, parents Herbert and Alice Symondson, residence Westmoreland Place, father is a musician, ceremony by H.H. Brown

In the 1901 census visiting with his brother Sidney at 58 Narleigh Road Civil Parish Preston, Ecclesiastical parish of St Saviour, Brighton Sussex. Registration District Steyning, Sub registration district Shoreham.
Herbert Symondson age 32, born at Hounslow, Middlesex, occupation musician.
Wife Alice Symondson age 24, born at Nottinghill, London.
Son Henry Symondson age 11 months born at Pimlico, London.

In the 1911 census “Ayredale”, Bury Street, Lower Edmonton, Middlesex.
Visitor Herbert Symondson, age 42, musician, theatre, worker, born Hounslow, Middlesex.
Visitor Alice Symondson, age 34, married 13 years, 3 children born alive, 2 still living, born Notting Hill.
Visitor Harry Symondson, age 10, school, born Pimlico.
Visitor Frank Symondson, age 5, school, born Pimlico.
They are staying with John and May Horner and family.
Also visiting is Frank Atwood a musician, conductor, employer.

In the London Electoral Registers 1926
51 Sutherland Street, Westminster
Alice Symondson
Henry George Symondson
Henry George Symondson (junior)

In the July to September 1926 marriage index Henry G. Symondson and Florence W. Mahony, St George Hanover Square, Middlesex, volume 1a, page 1119.

Parish Records St. Gabriel, Warwick Square, Pimlico, Westminter, London
Marriage July 10, 1926
Henry George Symondson, age 26, bachelor, civil servant, residence 51 Sutherland Street SW1, father Herbert George Symondson, musician and
Florence Winifred Mahony, age 29, spinster, clerk, 81 Westmoreland Street SW1, father John William Mahony, builder
after Banns by W. R. Browne
In the presence of J. W. Mahony [bride’s father?] and A. Symondson [groom’s mother?]

1939 England and Wales Register
30 Sussex Street, Westminster, London
1. Henry Symondson, born April 17 1900, married, turf commission agent
2. Florence W. Symondson, born December 30 1896, married, unpaid domestic duties

In the July to September 1981 death index, Henry George Symondson, born April 17, 1900, Surrey Mid Eastern District, Surrey, volume 17, page 0181.

National Probate Calendar
Henry George Symondson of 72 Greenhayes Avenue Banstead Surrey died 27 August 1981 Probate Brighton 17 November 1981.

Florence Winifred Mahony listed in the January to March 1897 birth index, St. George Hanover Square, London, Middlesex, volume 1a, page 447.

In the 1901 census 85 Coleshill Buildings [This is a few doors down from her future husband’s uncle Alfred Stuart Symondson at 104 Coleshill Buildings], Belgrave, St. George Hanover Square, London.
Head John Mahoney [as spelled], age 30, paperhangings salesman, born Chelsea, London.
Wife Alice Mahoney, age 24, born Pimlico, London.
Daughter Ethel Mahoney, age 5, born Pimlico.
Daughter Florence Mahoney, age 4, born Pimlico.
Son William Mahoney, age 2, born Pimlico.

In the 1911 census 37 Commercial Road, Pimlico SW London.
Head John William Mahony, age 40, painter, born Chelsea, London.
Wife Alice Mahony, age 35, married 16 years, 4 children born alive, all living, born Pimlico, London.
Daughter Ethel May Mahony, age 15, dressmaker, born Pimlico.
Daughter Florence Winnifred Mahony, age 14, born Pimlico.
Son William James Mahony, age 12, born Pimlico.
Daughter Ivy Beatrice Mahony, age 2, born Pimlico.
Their dwelling has 2 rooms.

In the July to September 1981 death index Florence Winifred Symondson, born December 30, 1896, Surrey Mid Eastern district, volume 17, page 0214.

National Probate Calendar
Florence Winnifred Symondson of 72 Greenhayes Avenue Banstead Surrey died 25 September 1981 Probate Brighton 13 November 1981.