Looks as though there is a furore going on about the Farmer's Market at Ally Pally. The management of Ally Pally seem to be insisting that less hot food be served to reduce competition with their own sales. This is the twitter conversation expressing outrage
(sorry, but my software does not support embedding it directly).
Broadly, it seems the management of Ally Pally have limited the number f hot food stalls at the Farmers' Market to four. Appears they fear the competition.