Hi
I'd love to help but struggling to find the address.
Old maps are here
https://maps.nls.uk/view/114594387 in 1903
https://maps.nls.uk/view/228800267 in 1887
The 1861 census has coming from Long Street on Market Street(just head of households)
William C Holland 61 Stationer still there in 1851
Hugh Stanton 55 saddler still there 1851
Joseph Morris 69 and Isabella 63 House proprietor and 1851
Market Place
James Burton 36 bookseller and 1851
Mary Nosworthy 37 Post mistress
Samuel Rowley 58 hair dresser and 1851
James Haddon 52 grocer
George Sale 85 retired draper and 1851
Ralph Crith 36 wine merchant
Thomas Bates 69 gardener seedsman 1851
Edward S Sanderson 29 school master
Chapel House Henry Power 59 solicitor also 1851
Market st
Eliza Finchback 50 governess Called Ivy Cottage in 1851
Ann Beach 72 fundholder there 1851
Jonathon Keene 50 cork cutter
John Barfoot 29 clock maker
Joseph Beech 44 grocer and druggist. and 1851
It then goes to Sheepy Head
Just no sign of St Mary's Court ,could it have been called something else before?
Swan entry perhaps?
In 1851 census extra entries Swan Yard
John Bates 52 milk seller with wife Mary 53
Joseph Fox 56 bricklayer and wife Elizabeth 60 ,daughter Hannah 16
Rebecca Vesey Allen milk seller 44
Ciderdrinker