Possible Clues:

• Musical group, or a hint to the ends of 20-, 37- and 52-Across
• Gold box artist makes musicians
• Group of players including scorer with hat trick
• Unbridled carthorse needs one with a stick to start
• eg Hallé
• Soldiers appearing on the box - Royal Artillery bandsmen?
• Rector has organised an alternative to the organ
• Gamelan, for instance
• Phil, some say, a royal playing for Liverpool
• Fiddling accounts for a few of these pit workers