I've looked at the other deaneries in Lincolnshire and can only find a couple of other entries:
Samuel ALLEN (widower) married Mary Susanna CHRISTOPHER in 1831 at Market Deeping
Samuel ALLEN married Amy WARD in 1826 at Langtoft
A search on the IGI throws up two possibilties:
Samuel ALLEN married Jane ALLEN on 23rd May 1820 at Church Broughton, Derbyshire
Samuel ALLEN married Jane CHAMBERS on 11th Sept 1820 at Melton Mowbray, Leicestershire
The Melton Mowbray entry is a strong possibility as its is only 17.3 miles away from Barrowby, whereas Church Broughton is over 50 miles from Barrowby.