There will be another mass march on Parliament by the activist group Anonymous on Saturday the 5th of November 2016. Meet up at Trafalgar at 6pm then at 6:30pm everyone will march down Whitehall to Parliament Square.

Given that this year this event falls on a Saturday it should be really huge!
Facebook event: https://www.facebook.com/MillionMaskMarchLondon/
Twitter: https://twitter.com/hashtag/millionmaskmarch?lang=en-gb

I don't think it is too early to announce this event as threads on this page seem to stay around for many months. And the earlier that this event is advertised and networked the bigger it will be. Wear a Guy Fawkes mask like this one if possible: