I checked the age again - Ancestry has transcribed it 27 so dob 1844 and name Marvill (I used Findmypast to find it originally) - there is enumerators mark through the age so I may be wrong about it being 37.
Maybe get second opinion from other listers?
Maybe there could be two Augustus MERRILL’s
1851c HO107/1472 page 1
Mary MERRIL Head Wid. 70 Liv…? Private Norwich, Norfolk
Marion dau wid 37 milliner “ “
Elizth dau u 27 dressmaker ? “ “
Augustus son 7 Middlx, London (transcribed as son of Elizabeth Merrill)
1861 RG9/349/43/31
Mary MERRILL Head Wid 46 Norwich, Norfolk
Augustus W son 17 Holborn St. Andrews, Middlx
1871 RG10/653/80/19transcribed
Augustus William MARVILL 27
Ellen Marin 26
Marian Louisa 14
Elizabeth Emma 7 mths
Original 1871 census age looks like 37 for Augustus
Augustus William MERRILL 37 Middlx, city oflondon
Ellen Maria 26 Westminster
Marian Louisa 4 Surrey Lambeth
Elizabeth Emma 7 mths “