Hi Pat
I'm inclined to believe the 1881 Benjamin you found is him :
1881 - Barking, EssexRef: RG11/1747, Folio 69, page 20
RD: Romford, Sub-RD: Ilford
Longbridge Cottages
Head: William G MURRELL age 66, Farm Labourer b Hyde Park, Middlesex
Wife: Elizabeth Ann MURRELL age 65, b Little Wakering, Essex
Grand-daugh: Adelaide M WALLIS age 10, b Upminister, Essex
Lodger: Benjamin ROWE 62, Farm Labourer, b Nr Colchester, Essex
Lodger: Mary A ROWE age 65, b Nr Southend, Essex
Despite Mary A's age being 65, when we would have expected abt 55 - her place of birth as Nr Southend does fit:.
Her age could be out, because the MURRELL's gave the information and did not know her right age or the enumerator incorrectly wrote 65 instead of 55 (the original clearly does say 65).
http://www.visionofbritain.org.uk/place/place_page.jsp?p_id=6907STAMBRIDGE (Great), a parish in Rochford district, Essex; 1½ mile E by N of Rochford, and 3¾ NNE of Southend r. station.
As to Benjamin's difference in age & birth places 1876/1871 again this could just be an error on the enumerator's part or a misunderstanding - it's certainly not an uncommon occurencce in the Census!
Then, the 1881 Benjamin, his age is right as you say but I can't discover how Nr Colchester might be a wide description for being born Great Wigborough or Great Wakering? Then again, Elizabeth MURRELL was born in Great Wakering, and one would assume she at least would know that Benjamin was from the same parts as she? The MURRELL's could be relatives too - perhaps thru Elizabeth.
As a caution though: in the 1861 Census for Barking, is a Benjamin ROW b abt 1811 Colchester - with a wife is named Ruth. He could be the same man as the 1881 man above with
his age all wrong & who has remarried......

This lark was never meant to be straight forward, I guess!

Cheers
AMBLY