MARRIAGE: Dec Qtr 1869, Warwick
Louisa BAYLISS
William SMITH
CENSUS 1871: 13 Albert Street, Birmingham All Saints, Warwickshire
RG10-Piece 3129-Folio 83-Pg31
Head: William BRENTING 29, Police Constable, b
Wife: Louisa BRENTING 24,
Son: William BRENTING 10 mths
Boarder: William SMITH 30, Police Constable, b Leamington Warwickshire
Boarder: Louisa SMITH 22, Leamington WarwickshireI think this is them - William's occupation is obviously different to that in later years; the marriage and his stated occupation there might clarify this.BIRTH 1877: Jun Qtr, Gloucester
Ellen Louisa SMITH
BIRTH 1880/1881: Mar Qtr 1881, Gloucester
Wilfred Bertie SMITH
(registry in the March Qtr, means he was registered either Jan-Feb or Mar 1881, and therefore could have been born late Nov/Dec 1880. Wilfred's census in 1911 Canada, states he was born Dec 1880).CENSUS 1881: 6 St James St, Gloucester (Barton), Gloucestershire
RG11-Piece 2536- Folio 96 -Pg 6 & 7
Head: William SMITH 39, R.R. Wagon Fitter, b Leamington Warwickshire
Wife: Louisa SMITH 34, b Leamington Warwickshire
Dau: Ellen Louisa SMITH 3, b Gloucester
Son: Wilfred Bartie SMITH 3 months, b Gloucester
BIRTH 1885: Mar Qtr, Gloucestershire
William SMITH
Probably the right Birth? The other Williams around the right time-frame have middle names.CENSUS 1891: 33 Victoria Street, Barton St Mary, Gloucester, Gloucestershire
RG12- Piece2017- Folio 70- Pg20
Head: William SMITH 49, Railway Wagon Fitter, b Leamington Warwickshire
Wife: Louisa SMITH 43, b Leamington Warwickshire
Son: Bertie W SMITH 10, Scholar, b Gloucester
F-in-Law: Thomas BAYLISS 73, b Leamington Warwickshire
Son: William SMITH 6, b Gloucester
Note: Daughter Ellen Louisa SMITH age abt 13 is not in the 1891 household. Cannot locate her elsewhere nor any death.
By the time of 1901 Census, the two sons are boarders in a household, below. I can't find a trace of their parents in 1901 - and wonder if these are their deaths:
DEATH 1898: Sep Qtr 1898 Gloucester, Louisa SMITH, age 50
DEATH 1901: Mar Qtr 1901 Gloucester, William SMITH, age 50
CENSUS 1901: 6 Pembroke St, Gloucester, Gloucestershire
RG13- Piece 2430- Folio 85- Pg7
Head: Mary E HILYER 43, widow, Needle Woman (plain sewing), b Gloucester
Dau: Euphemia W HILYER 13, b Cheltenham
Dau: Marion L HILYER 9, b Cheltenham
Sister: Marion P STEPHENSON 58, single, b Scotland
Boarder: Alfred F REED 25, single, Engine Fitter, b Falmouth, Cornwall
Boarder: Wilfred B SMITH 20, single, Wheelwright's apprentice, b b Gloucester
Boarder: William SMITH 16, Carriage maker's apprentice, b b GloucesterIt's somewhat unusual for the place & times, that from Marriage 1869 until Census 1891 (when Louisa is nearing the end of her child bearing capable years), there are only three known children with the first a long 8 years after the marriage :
* Ellen Louisa SMITH 1877
* Wilfred Bertie SMITH 1880
* William SMITH ~1885
(This points to there perhaps having been a problem with fertility or in bringing a pregnancy to term, or early childhood deaths)
So it looks like your grandfather 'Bertie' (Wilfred Bertie) only had 2 siblings.The Gauntlet is thrown, Rootschatters: 
Can't find Ellen Louisa SMITH after the age of 3 in 1881.
And the beautifully named William SMITH, is perhaps going to be a challenge to find !
Cheers
AMBLY