Rushy
basically a scrotum
I'm going to guess that they've considered the Brixton Pound Café, given that two of its directors are named as part of the management team.Other ideas- the library, Brixton pound cafe, St mathews church, Brixton advice center....
Advice Centre is probably too far away from sources of food (central traders) which is a key consideration according to the planning application.
St Matthews is mostly commercial operations (restaurant and offices). The building managers can't even afford basic security for their commercial rentals (most of the building), let alone support this (The Brix has apparently been disbanded). If you read their 2016 planning application for the peace gardens, they are actively trying to discourage people such as the homeless from hanging about anyway. The small area still operating as a church is not reliably accessible.
Library - good central location. No idea about other practicalities.
The idea (not yours, I know) that Market Row and Brixton Village would comfortably overcome the alleged demographic obstacles to pop is patently laughable.
Let's not forget that the purpose of this is not specifically to "feed the needy". It is to raise public awareness of food waste issues, and that needs to be very visible in places which people most likely to contribute towards generation of excess food frequent.