Ruskin Park’s promotion chances all but disappeared when they crashed to a 29-10 defeat at Port-e-Chee in South Lancashire/Cheshire Division Two.
Will Latta was the star for Douglas picking up two tries. There were also scores from Simon Heggs and Christian Brew, plus two conversions and a penalty from Mike Hebden.
Orrell Anvils guaranteed their promotion with a 20-3 win over Ramsey at Mooragh Park.
Ben Harding kicked Ramsey’s only points of the afternoon in what was a disappointing finish to the season for the Manx side.