The Islanders had defeated Bristol Pitbulls to reach the final, while the Warriors progressed after defeating Cardiff Fire.
Clint Herring (2) and Nathan Pollard (2) topped the scoring in the first leg of the final as Peterborough romped to a 9-1 road success.
Brandon Ayliffe’s hat-trick helped Chelmsford restore some pride in the return game with a 5-4 win, but the Islanders end the campaign with the regular season regional title, the D2S Cup and play-off crown to their name.
Chelmsford Warriors 1-9 Peterborough Islanders
Peterborough Islanders 4-5 Chelmsford Warriors
(Image permission: Tom Scott)