Pie in the Sky (1994) : 5x4

Henry and his team are called to a private boarding school where police Commander Colin Stilwell's son Alex has been beaten up by local youths. Henry initially encounters a wall of insular hostility from the establishment before Alex points him to another pupil, who has blackmailed the Chemistry teacher into manufacturing Ecstasy tablets, which he is selling around the school. Gary meanwhile creates a new blend of mustard and attracts the attention of a large food manufacturer who offer to market it. However, they want to alter the recipe, making it taste more bland, whereupon Gary, taking a leaf from Henry's book, puts his culinary principles first and tells them that the deal is off.