Following that family through in censuses, in 1861 Elizabeth gives her birthplace as Wing, Bucks, so they may not have married in Beds. In 1851 and 1861 they had a daughter Caroline whose birth appears to have been registered in the Sept quarter 1841 in Luton. Buy the cert to get Elizabeth's maiden name. They may have been the James Burd and Elizabeth How who married in Caddington on 18 Feb 1819, although Elizabeth looks a bit young to have married in 1819. Caroline's birth cert will either confirm it or rule out the Caddington marriage.