Report of rough sleeper crossing island (7)
I believe the answer is:
dossier
'report' is the definition.
(I've seen this before)
'rough sleeper crossing island' is the wordplay.
'rough sleeper' becomes 'dosser' (I've seen this before).
'crossing' indicates putting letters inside (to cross can mean to go over or around).
'island' becomes 'i' (geographical abbreviation).
'dosser' enclosing 'i' is 'DOSSIER'.
'of' acts as a link.
(Other definitions for dossier that I've seen before include "Papers containing detailed information about a particular person" , "A collection of papers" , "Collection of documents on a subject" , "Set of documents about person" , "File of documents" .)