Virtually all of Beds pre 1812 is on the IGI, including Luton St Marys. If it's not there, which it isn't, they married elsewhere, probably in another county which is isn't as well covered on the IGI.
Luton is very close to Hertfordshire. I would ask for a look up on the Herts board for the marriage on the Allen Marriage index
David
Logged
Census information is Crown Copyright, from www.nationalarchives.gov.uk Beds: Cople: Luke/Spencer Everton: Hale Henlow: Cooper/Watts/Sabey Potton: Merrill Southill: Faulkner/Litchfield/Sabey Woburn/Husborne Crawley: Surkitt Hunts: Gt Gransden: Merrill/Chandler/Medlock Toseland: Surkitt/Hedge/Corn Cambs: Bourn: Bowd Eltisley: Medlock Graveley: Ford/Revell