Hospital doctor from triage's moving into middle of Harrow (9)
I believe the answer is:
registrar
'hospital doctor' is the definition.
(I've seen this before)
'triage's moving into middle of harrow' is the wordplay.
'moving' is an anagram indicator.
'into' is an insertion indicator.
'middle of' says to take the centre.
The central letters of 'harrow' are 'rr'.
'triages' with letters rearranged gives 'egistra'.
'egistra' inserted inside 'rr' is 'REGISTRAR'.
'from' is the link.
(Other definitions for registrar that I've seen before include "Official record-keeper" , "University official" , "Official record keeper" , "Wedding recorder" , "Mid-ranking doctor" .)