Clue: Trouble: money mislaid at the back of inspector's carriages — it ends in Lost Property (9)
Answer: DISTRAINT
Explanation: Definition: it ends in Lost Property
A charade of DI'S ('inspector's') plus TRAIN ('carriages') plus 't[rouble] minus ROUBLE ('money mislais'). Distraint is the siezure of goods for a debt.