### Clue: Note on mobile model about start of regeneration for tardis user (4,4)
### Answer: TIME LORD 
 ### Explanation: Definition: tardis user
 TI(the seventh note of a major scale in music) **placed above**(on, in a down clue) **anagram of**(mobile) MODEL **containing**(about) **1st letter of**(start of) "regeneration".
Defn: What Dr. Who – the TV series character with his time machine, the TARDIS – was. It's now a she-lord and her time machine: