Part-time judge has request again about start of case (8)
I believe the answer is:
recorder
'part-time judge' is the definition.
(I've seen this before)
'request again about start of case' is the wordplay.
'request again' becomes 'reorder' ('order' is an answer for 'request' so perhaps 'reorder' is OK for 'request again').
'about' means one lot of letters goes inside another.
'start of case' becomes 'c' (I can't justify this - if you can you should believe this answer much more).
'reorder' placed around 'c' is 'RECORDER'.
'has' is the link.
Can you help me to learn more?
(Other definitions for recorder that I've seen before include "Wind instrument - historian, perhaps" , "sound device" , "Instrument of the flute family" , "Musical instrument or note-taker" , "The one who takes notes and a tubular wind instrument" .)