De Beauvoir Gardeners?
Hi there, you have commendable lateral thinking! Have you tried a group called the de Beauvoir Gardeners? They are based in the area just south of Dalston Junction. Not sure how big their gardens are but it’s worth checking them out. Celia (? not sure of her surname) from the group writes a column in E8 magazine. Otherwise, I wonder if you might have more luck a bit further out of town where people might have bigger gardens.