### Clue: Serviceman's mistake over a little work (6)
### Answer: BISHOP 
 ### Explanation: Definition: Serviceman
  BISH(British slang for "a mistake") **placed above**(over, in a down clue) OP(abbrev.;little for "opus", a musical work).
Defn:  Not your car mechanic nor a military man, but the one who leads (or gets someone from his organisation to lead) the service in church.