This is what I've been able to find so far, I'm not sure you can find much else online at least:
(Season - Winner, Runners Up)
56/57 - Trowbridge Town, Bideford
60/61 - Exeter City Reserves, Dorchester Town
82/83 - Frome Town, Plymouth Argyle Reserves
83/84 - Dawlish Town, Frome Town
92/93 - Tiverton Town, Clevedon Town
93/94 - Tiverton Town, Taunton Town
94/95 - Elmore, Tiverton Town
95/96 - Tiverton Town, Barnstaple Town
96/97 - Tiverton Town, Chippenham Town
97/98 - Tiverton Town, Taunton Town