### Clue: Having nap in an old car shows advancing years (4,6)
### Answer: ANNO DOMINI 
 ### Explanation: Definition: advancing years
 NOD(to nap) **contained in**(Having … in) [AN + O(abbrev. for "old") + MINI(short for the iconic British car) ].
Defn: … after the traditionally reckoned year of the birth of Jesus.