alasta: This page would seem to indicate that indoor and outdoor events can go ahead in the orange setting without headcount limits.In the red setting there appears to be a headcount limit of 100 which would mean that events would have to be cancelled, but the government backed event insurance scheme means that event organisers won't need to announce cancellations until it becomes clear that they will be affected by the red traffic light at the time of their event.
Chosen certificate controlled events. Good luck with Open invite Public ones lining the streets with no fencing. Like fireworks or Christmas parade.
These places will not be able to operate without a vaccine certificate requirement:
events (indoor/outdoor)
Green no cert has 100 limit also.