Drink I'd found in park heading north (5)
I believe the answer is:
cider
'drink' is the definition.
(cider is a kind of drink)
'i'd found in park heading north' is the wordplay.
'found in' is an insertion indicator.
'park' becomes 'rec' (I've seen this in other clues).
'heading north' says the letters should be written backwards.
'rec' back-to-front is 'cer'.
'id' inserted inside 'cer' is 'CIDER'.
(Other definitions for cider that I've seen before include "Drink made from pears" , "Alcoholic drink (to be taken with Rosie?)" , "Alcoholic drink made from apples" , "Beverage from apple juice" , "Alcohol from apples" .)