There is an Abraham and Mary Mauchet, aged 80 and 75 (ages rounded down to the nearest 5 years) living in Anderson's Walk, St Mary, Lambeth in the 1841 Census. Abraham claims Independent Means. Both were NOT born in Surrey.
Reference HO107/1057/6 page 6.
I would say it is probable that these are the Abraham and Mary you have found on the IGI, christening a Samuel.
In case you don't have the Joseph family, they are at Regency Place, Lambeth in 1841. Same street as 1851. HO107/1055/1 page 37....
Francis Joseph 70 Laborer
Sarah 50
Mary 20
John 19 Carman
William 17 Barman (not Carman)
Robert 11 Shopboy
James 8 Shopboy
Alas, no sign of Samuel.
Nigel