River forded at Griffin Park (5)
I believe the answer is:
brent
'forded at griffin park' is the definition.
I can't judge whether this definition defines the answer.
'river' is the wordplay.
I cannot really understand how this works, but
'river' could be 'r' (abbreviation) and 'r' is located in the answer.
The remaining letters 'bent' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for brent that I've seen before include "kind of 10 [GEESE]" , "Borough of NW London" , "West London borough" , "Lofty" , "Type of goose - London borough" .)