Have you checked out the Dorset OPC pages for Shaftesbury St James ?
http://www.dorset-opc.com/ShaftesburyFiles/St.James/St.James.htmThere are the following marriages ... and may be more ...
1629 Thomas BRUER & Sarah MAPOWDER were married 23-Dec
1630 Robert MAPOWDER/CLARKE & Petronilla LACIE were married 30-Jun
1635 Giles RANDOLL & Joan MAPOWDER were married 27-Apr
... and I'll leave you the fun of searching through their other lists for baptisms and burials ...
It would be worth you putting 'Mapowder' into the main Dorset OPC search facility ... as I say, I'll leave it up to you !
(I'm enjoying this ... its the name that's caught my attention !)
Have you also tried putting his name into Google ? He occurs in 13 entries, but one is from the reply I gave you about the NA yesterday ! Google is obviously on the ball !