Jon,
They did not actually get married at Holy Island but are registered as married Lamberton Toll. Sometimes the pastor recorded marriages done in Scotland if they were members of his parish
Lamberton 29 Nov 1812
"These are to certify all whom it may concern that Ralph Barker and Elizabeth Dickson were solemnly united by me in the holy bonds of wedlock according to the rules of the Church of Scotland and they are free from all church censure? so/or as it is known, James Aitchison
Witnesses: John Hedgley, Ann Millar, Morton? Clark and Mary Ann Clark
The above is a true copy of the certificate brought to me Dec 1st 1812 of the marriage of Ralph Barker and Elizabeth Dickson both of Holy Island, Lancelot Wilson, Minister
Janis