Country product on the market in London (3)
I believe the answer is:
hay
'london' is the definition.
Although both the answer and definition are singular nouns, I can't understand how one could define the other.
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for hay that I've seen before include "Wye book town" , "Animal fodder" , "It is to be made while the sun shines" , "Cut and dried grass" , "Dried mown grass" .)