Hello
I can see possibly 2 William Gregory deaths registered in Manchester 1851-1861
William Gregory age 64 June 1856 8D 89 Which has a Will at Lancashire Archies for a widower coachman .
William Gregory age 72 died March 1859 Manchester 8D 248
Elizabeth Gregory Chorlton Mar 1853 age 63 8C 391
Elizabeth Gregory Dec 1854 age 64 8C 319
Elizabeth Gregory 69 Sep 1861 Chorlton 8C 363
Going through registration for Manchester ,Chorlton and Salford.
So which is nearest to Elizabeth St ,St Barnabus from the 1851 census and ages 74 and 69 ?
None of them are shouting out to me.
You could try looking at Manchester Councils locate a grave site
https://www.burialrecords.manchester.gov.uk/Ciderdrinker