Unpleasant argument in Hyde Park (6,3)

I believe the answer is:
rotten row
'hyde park' is the definition.
I know nothing about this answer so I can't tell whether this works.
'unpleasant argument' is the wordplay.
'unpleasant' becomes 'rotten' (I've seen this before).
'argument' becomes 'row' (to row is to argue).
'rotten'+'row'='ROTTEN ROW'
'in' acts as a link.
Can you help me to learn more?
(Other definitions for rotten row that I've seen before include "Once fashionable avenue for riders in London" , "Horses here" , "Where to see riders" , "Track through Hyde Park" , "Part of London park" .)
