There are some wills for Montagues in Hertfordshire, a bit earlier:
PCC wills:
1773, William Montague, of Park Street, St Stephen, maltster
Daughters Sarah, Elizabeth, Mary
Son and executor William
1774, William Montague, of Watford, victualler
Wife and executrix Susannah, no children mentioned
1781, Giles Montague, of Berkhamstead St Peter, innholder
Wife Ann, no children mentioned
William Montague, son of late deceased uncle George Montague, blacksmith
John Montague, another son of George Montague
Wills at Hertford:
1791, Daniel Montague, of Kimpton, husbandman, register will and filed will
1791, Elizabeth Montague, of Kimpton, widow, register will and filed will