Hi Marg,
Edmonsham (1841 census) is in the district of Wimborne, which covered a much larger area than "Wimborne" does today. Edmonsham is close to Wimborne St. Giles, a small village and about 10 miles north-east from Wimborne Minster, a much larger place. I live in this area.

If you look at the registration details on FreeBMD there is a facility to "click" on to the registration district which lists all the places that it includes.
The Alderbury registration district covers a large rural area in south Wiltshire near to both the Dorset and Hampshire borders.
Perhaps Mary was in service and away from home; it would be useful to see if her family could be found on 1851 census.
If you send for the marriage certificate, stipulating that the bride's father is James, and the records do not match, then you get a partial refund.
Nanny Jan