Putting the information together gives:
TIMELINE
1800 Seprina TAYLOR born/baptised in Halkyn, Flintshire
1822 Seprina TAYLOR married John OLDFIELD
1833 John OLDFIELD died in Manchester
1841 census William MALCOLM, Sebrina MALCOLM and OLDFIELD/MALCOLM children together
to 1843 William MALCOLM ratebook holder for 49 Hardman Street
1844 onward Seprina MALCOLM ratebook holder for 49 Hardman Street
1851 census Seprina OLDFIELD at 49 Hardman Street widow with 2 sons
1851 census William MALCOLM in Austin Court, widower with 1 son
1852 death of William MALCOLM (buried at Rusholme)
1859 death of Seprina OLDFIELD
CENSUS INFORMATION (cited by rosie99 on other thread)
1841 census H107/569 bk 2 f7 p8, Lancashire
William Malcolm bn Ireland
Sebrina Malcolm not bn in County
John Oldfield 15 not bn in County
Richard Oldfield 15 not bn in County
William Oldfield 10 not bn in County
Henry Oldfield 7 born in Ireland
Sarah Malcolm 5 bn in County
Frederick Malcolm 3 bn in County
(ADDED & edited 5 Jun) FreeBMD transcriptions added to rosie99's info
1851 census HO107 2227/88 p7
Hardman Street, Manchester, Lancashire
Seprina Oldfield, head, 28, widow, lodging house keeper, born Wales
John Oldfield, son, 28, married, working jeweller, born Wales
Frederick Oldfield, son, 13, scholar, born Manchester
William Fisher, lodger, 48, widower, attorney clerk, born York
William Henry Rouson, 0, nurse child, born Manchester
1851 census HO107 2227/100 p30 (surname transcribed as MALCORN!)
1 Austin Court, Manchester, Lancashire
William Malcom, head, wid, 42, general vault porter, born Manchester
William Henry Malcom, son, unm, 17, general vault porter, born Manchester
BMDS
garstonite found (shown on other thread, quoting sources):
MALCOLM William Henry bapt 1837 age 3
MALCOLM Sarah Ann Seprina bapt 1837
MALCOLM Sarah A buried 1843 age 6
maddys52 found:
MALCOLM George Frederick bapt 1838
There is a possible death on GRO (General Register Office)
Dec qtr 1852 Manchester vol 8d p110 - MALCOLM William age 50
Philip