Mersea Island 24, West Norfolk 15
West narrowly missed out on a bonus points as they slipped to their second defeat in a row.
The North Wootton outfit were 10-0 up at the break thanks to a Will Dodds try and a penalty and conversion from Paul Denton.
But the hosts powered back into the game and Nigel Richardson's charges could only add a further score when Ed Maule crashed over.
West remain eighth in the 12-team table with four games left.