The info comes from the ERs on Ancestry. Janet is definitely on the right track. The marriage is the right one as John appears as John Blackford Murray on later ERs with 3 of his children named in the 1911 census.
Elizabeth Jones age 75 visitor I believe is Elizabeth Murray's (nee Love Jones) mother.
Born Elizabeth Sinfield in Lidlington Bedfordshire c1836 married a John Jones 1860 Ampthill.
Still looking for them in 1861.
By 1871 Elizabeth Jones is a widow & Elizabeth (Love) Jones age 8 born Islington is living with her aunt Love Jones, single age 48 in Wellingborough.
Another possible daughter of Elizabeth & John Jones is Katherine Love Jones born c1865 Islington. In 1871 she is living with her Sinfield grandparents in Lidlington.
Of course there may be other children from the 1860 marriage & this is where Constance Beatrice fits in. Still working on that idea at the moment.