Sony mobile carried by highly-strung chauffeur who's always interfering (4,6)
I believe the answer is:
nosy parker
'chauffeur who's always interfering' is the definition.
I can't tell whether this definition defines the answer.
'sony mobile carried by highly-strung' is the wordplay.
'mobile' is an anagram indicator (mobile can mean moving).
'carried by' says to put letters next to each other (in a down clue, some letters hold up others).
'highly strung' becomes 'parker' (I am not sure about this - if you are sure you should believe this answer much more).
'sony' with letters rearranged gives 'nosy'.
'nosy'+'parker'='NOSY-PARKER'
Can you help me to learn more?
(Other definitions for nosy parker that I've seen before include "Prying person" , "Interested party" , "busybody" , "snoop" .)