### Clue: Service industry job ends up in a class of its own (2,3)
### Answer: BY FAR 
 ### Explanation: Definition: in a class of its own
 **Reversal of**(up, in a down clue) [ RAF(abbrev. for the Royal Air Force, a service branch of the British military) + **the last letters, respectively, of**(… ends) "industry job "] .