Have re written for completeness
Witness Maud MATHEWSONCould be
Maud Caroline LUMLEY/LUMBLEY who married Percy MATTHEWSON in 1919
1921 2 Gibbon Yard, Bridge St, GainsboroughMaud C. MATHEWSON age 21y 3 mth. Married Born Goole, Yorkshire
Winnie MATHEWSON, dau 6 months bo Gainsboro’ Lincs
Rina/Rena MATHEWSON 22y 6 mths. Married born Huddersfield, Yorkshire
Percy is in the Army - his record is on ancestry. Says there is a son Percy.
1921 Workhouse InfirmaryPercy MATHEWSON 1 yr 8 mths both parents alive. Born Gainsboro’
There were other children, before Maud died in 1928. But this family is not the one in question

However.
Percy senior born age 21 y 11 mths is in some barracks in Gainsborough
in 1921 is married, born
Blyth, Nottinghamshire, He is a private in the army infantry and has 2 children.
1911
on Bottesford MoorCharles MATTHEWS head, 55, Rag & Bone Dealer 9 children 8 living. b Bolton Lincs
Emily 58 born Winteringham, Lincs
Albert 15 b Boston
Ellen 13 b Gainsboro’
Percy 11 b Blyth, NottinghamshireEmily 8 b Scunthorpe
Ernest 5, b Barrow
Filled in by J. H. Sanderson.
1901 Family of gipsies living on East Common in a tent - parish of St Lawerence, Frodingham
Charles MATHIESON head 42, Gipsy Hawker b Bostson
Emily 32 b Winterhingham
Lizzie 14 b Hook, Yks. (which is essentially Goole) John Ed. 12 b Boston
Frederick 10 b Lincoln
Albert 7 b Boston
Nellie 4 b Gainsborough
Percy 2 b Blyth, NottsIf this Lizzie is the woman who married Fred GREEN senior,
which seems likely to methen Percy is Fred junior’s uncle (although only 7 or so years older).
And the family found by Castallic is the correct one.