Robert Brooks tells me that their marriage certificate shows they were married at the parish church of St Mary's Stratford Bow, Poplar.

Chris Dufton's Family History web site shows us the following information about Robert George East:

1851 living at 14 Essex Street, Bethnal Green, London, Robert East, Son, Age 7, Born Standon Herts, Scholar .
1861 living at 3 Langport Place, Lambeth, London, Robt G East, Son, Age 17, Born Standon Herts, Engineer .
1871 living at 26 Whitaker, Litchurch, Derbyshire, Robert G East, Head, Age 27, Born Standon Herts, Mechanical Draughtsman .
1881 living at 88 Uttoxeter New Road, Derby, Derbyshire, Robert G East, Head, Age 37, Born Standon Herts, Mechanical Draughtsman .
1891 living at 459 Harrow Road, Chelsea, London, Robert G East, FinLaw, Age 47, Born Standon Herts, Draughtsman .
1901 living at 9 Alma Road, Wandsworth, London, Robert G East, Head, Age 57, Born Standon Herts, Mechanical & Mining Engineer .
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We can see Robert East and his wife in 1881 living at 88 Uttoxeter New Rd, Derby, England

Robert G. EAST Head M Male 37 Standon, Hertford, England Mechanical Draughtsman (E & M Maker)
Frances EAST Wife M Female 31 St Georges East, Middlesex, England
Alice R. EAST Daur Female 12 Earls Colne, Essex, England Scholar
Augustus G. EAST Son Male 10 London Bow, Middlesex, England Scholar
Ada F. EAST Daur Female 9 Derby, Derby, England Scholar
Edith E. EAST Daur Female 7 Derby, Derby, England Scholar
Arthur R. EAST Son Male 5 Derby, Derby, England Scholar
Henry T. EAST Son Male 4 Derby, Derby, England
Frederick W. EAST Son Male 1 Derby, Derby, England
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In 1891, we can see the family living at 459 Harrow Road, Chelsea, London:
Samuel Bryan Head 26 Furniture (?) South Wirham Lincs
Alice R Bryan Wife 22 Earls Colne
Robert G East F in Law 47 Draughtsman Herts Standon
Frances East Wife 41 London Stepney
Frances A East Daur 19 Teacher of Music Derby
Edith E East Daur 17 Teacher of Music Derby
Arthur R East Son 15 Furniture (Apprentice) Derby
Henry T East Son 14 Scholar Derby
Frederick East Son 11 Scholar Derby
Herbert C East Son 10 Bloomsbury London

Samuel Bryan was the brother-in-law of Robert East. Samuel married Robert's sister Alice in q1/1888 at Paddington District, London.
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In 1901, Robert was living at 9 Alma Road, Wandsworth, Surrey:
Robert G East Head 57 Mechanical & Mining Engineer Standon Herts
Frances East Wife 51 London Stepney
Arthur R East Son 25 Mariner Derby
Jan Rugert van Schuyman S in Law 24 Accounts Clerk Chesire Sydney Creise(?)
Edith E van Schuyman D in Law 24 Derby Derby
Arthur J van Schuyman Gson 10 mnths London Clapham Junction
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In 1911, Robert and Frances were living at 2 Sherwood Road, Wimbledon, Surrey:
Robert George East Head 67 Engineer Now Out of Work Standon Herts
Frances East Married (43 years) Wife 61 Stepney London
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I'm told by Robert Brooks, a descendant of his, that Robert served an apprenticeship to an engineer and millwright based in Southwark, London. The indentures are signed by Robert George and his father Robert. It's believed that he then attended Trinity College, Dublin completing a mechanical engineering course/degree. He worked on plans for the Mersey tunnel and a project for a Humber bridge.

Robert hasn't been able to establish where or when he died, but believes he and Frances were buried in Chesterfield, where one of their son`s lived.

Frances East, taken in about 1900, aged 50 - click to enlarge.

Frances' father, Henry Theodore Knibbs isn't related by blood to the Knibbs family. His parents were John and Ann BURT so his real name is Henry Theodore BURT. Henry's mother was widowed and then married Francis Knibbs (1793-1856).
Henry married as Henry Theodore BURT but at a later date, he assumed the surname KNIBBS.

Francis was born in 1850, but we believe it's her recorded as FranCIS rather than FranCES in the general register.

We learn from Chris Dufton that Alice married Samuel L Bryan on 25 Feb 1888 in Paddington, London, Middlesex, England

We learn from Chris Dufton that Augustus married Florence Mary Massey in Dec 1896 in Loughborough, Leicestershire, England

Frances married a man named George Winfield in 1896, probably in Chesterfield.

We learn from Chris Dufton that Edith Ellen married Jan Rutgert Schuymer on 4 Nov 1899 in Wandsworth, London, Middlesex, England.

We learn from Chris Dufton that Henry Theodore east married Florence Edith Schuymer in Sep 1899 in Leeds, Yorkshire, England.

Frederick married Frances Rose Ward on 6 Nov 1909 in Wandsworth, London, England. They had 7 children. His wife Frances was born on 25 Jul 1882 at Clondalkin, South Dublin, Ireland.

Herbert married Mabel Ellen Morris on 24 Dep 1904. Mabel was born in Cardiff, Wales c.1880.