### Clue: Penultimate bus at Barking left before time I arrived (4,3,3)
### Answer: LAST BUT ONE 
 ### Explanation: Definition: Penultimate
 [ **Anagram of**(… Barking/mad) BUS AT **placed below**(… before, in a down clue) L(abbrev. for "left") ] + T(abbrev. for "time") **plus**(… arrived?) ONE(number represented by Roman numeral "I").
Does "arrived" indicate the addition/presence of "ONE"?