http://www.bbc.com/sport/0/football/30661045 Reading that it seems like we have overpaid to keep ourselves out of a tribunal, i would guess its around 100,000 level due the word 'happy' being used to describe the fee from the Brentford end... were better on the free agents list
"Both sides have agreed not to disclose it but I can tell Brentford fans that we are happy that we will be adequately compensated if Luke continues to develop," I read it to say they have negotiated a good sell on clause.