Clue: Herb trumpeting prelate not fully organised (6)
Answer: ALPERT
Explanation: Herb trumpeting prelate not fully organised (6)
***(prelat)** [anag:*organised*] i.e. [*not fully*] PRELAT(e) 
*Herb Alpert is an American trumpeter and frontman fro Herb Alpert and the Tijuana Brass.