Property document: hint of trouble it conveyed about river (5,4)
I believe the answer is:
title deed
'property document' is the definition.
'title deed' can be an answer for 'document' (title deed is a kind of document). I'm not sure about the 'property' bit.
'hint of trouble it conveyed about river' is the wordplay.
I cannot quite understand how this works, but
'it' could be 't' (abbreviation. e.g. in 'tis) and 't' is located in the answer.
'river' could be 'dee' (River Dee) and 'dee' is located in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for title deed that I've seen before include "Document establishing legal right to property" , "Document proving ownership" , "Having proof of ownership" , "proper document" , "Document giving legal right of ownership" .)