Are you thinking of "bloody murders" (common in crime fiction or horror) or perhaps "bloody Marys" (the cocktail)?
Is it possible "matures" was intended to be another word, like "bloody matures" for "bloody amateurs" ? This is a very common phrase used to describe someone unskilled. To help me track down the specific text, could you share: bloody matures
In British slang, "bloody" is often used as an intensive. "Matures" could refer to a specific group (e.g., "Those bloody matures are at it again"), though this is not a standard idiom. Are you thinking of "bloody murders" (common in