I have trawled through the Ancestry images of the Duffield registers for that year and a year either side but with no luck. I will look on family search to see if they are the same set of images.
You say here you have looked at the images 'a year either side'.
My advice would be to look at AT LEAST 5 years either side of any date when researching anything.
Before birth certificates in 1837, not everybody knew exactly when they were born, or even exactly where.
There may be any number of reasons why.
Also, as of now, people may have other reasons for 'stretching the truth'.
If she was born in 1796 and married in 1820, she would have been 24. Do you know how old Daniel Revell was? Perhaps she altered her age to fit with his - either older or younger. (I have several cases of people being 'economical with the truth'!).
Or perhaps she had always been told that date by her parents and it was incorrect for whatever reason - you were born 'the year of the big storm' could have one of several!
Have you traced Joseph White the witness at the marriage?
There would be a good chance he would have been a relative of some sort - perhaps her brother.
His baptism? where he is the Censuses? when he died? etc.
Did he have any children? There's a good chance he may have named his first son, or another son, after his father.
Same goes for Margaret's children. Did she have any sons? Do the names tally with those on Daniel Revel's side? Perhaps one was her father's name.
Another avenue to go down is looking at wills.
Perhaps Joseph (above) left a will and mentions his sister?
Derbyshire wills pre 1848 are on findmypast under the Diocese of Lichfield.
You could do a general search for 'White' in Duffield, and other surrounding places.
I see in the Staffordshire Names Index (which unfortunately only goes up to 1790 at the moment), there is a will for a William White in Duffield 1776, and another in Shottle, Duffield in 1770. A bit early I realise, but there may be others on findmypast later than that.
What about Daniel Revel? Did he leave a will, or his father or grandfather? Perhaps they mention his wife or her family. You never know what might might turn up in wills.
Just some ideas to think about.
Good luck