In the first half there was little difference between the two sides, with both teams defences being tested, in particular when Boston were reduced to fourteen players as first Mathew Deane and then Wayne Harley were yellow carded.
Sean Bishop opened the scoring with an intercept try, before Matt Bray added the conversion and a subsequent penalty.
The visitor's scored a converted try to cut the half-time gap to 10 -7.
But Boston took the game away from them with tries from Matt Bray and a rapid-fire double from winger Thomas Loveley.
The final try by Rowan Mason ended a compelling second half performance from Boston.