Is this the one you mean in 1861, it's the only one I can see?
RG 9; Piece: 75; Folio: 15; Page: 25
15, Adam Street East, Marylebone (not the same as you give)
Richard S Morgan 22
Elizabeth Morgan 23
John Lawless 52 married Coach Maker Gowsom, Ireland
There is no relationship give to the Morgans, so I think it could be that he was a separate household. No one else there.