Personally I never noticed that the BE g/g puree method was particularly stronger. I know Bruce said there was a chemical reason, but never elaborated.
I've tried a few things with fresh chillies (cold water puree, hot pre-fry...) and the most I've achieved is an added "bite", but not a "last 5%" sort of achievement.
As an experiment, why not a add a new fresh (or dried) chillies to the curry and remove at the end? (or don't eat). This was something I stumbled on with Admin's Jalfrezi.
-- Josh