This may not affect people in Sydenham overly much, but bearing in mind the number and nature of the problems caused by last September's Wireless Festival at Crystal Palace the organisers, Festival Republic, say they want to work with locals to provide a better experience this year. They've already held some in-person and Zoom meetings, so if you want to be included in the rest please see https://www.festivalrepublic.com/crysta ... residents/ , which is where details of this year's proposals can be found.
NB: Wireless is not the only major festival occurring in the Park this year, and there are a number of other events, run by different organisers.