Hi Ducie,
The Sussex Marriage Index has the following:
Place: South Malling, East Sussex
Date: 3 Mar 1822
Subject: Samuel HILLMAN, bach
Spouse: Rebecca COLWELL, wid botp (B)
There is no further information when Rebecca is the subject.
The only marriage in Sussex of a Rebecca to a Colwell around the right time is this:
Place: Lewes St. John sub Castro, East Sussex
Date: 28 Nov 1819
Subject: William COLWELL, Cliffe
Spouse: Rebecca NORMAN, otp (Lic)
When Rebecca is the subject her spouse is more fully described as of St Thomas, Cliffe.
The SMI has the licence:
Archdeaconry of Lewes Marriage Licence
Date: 26 Nov 1819
Subject: William COLWELL, b cabinet maker S.Thos in Cliff Lewes
Spouse: Rebecca NORMAN, s St.Johns Undercastle Lewes
Additional information when Rebecca is the subject - both are aged 21+ (so Rebecca's year of birth doesn't quite fit with your census data).
HTH,
Stovepipe