From what I vaguely remember from last year, I went to nights 5 & 6 in September, Will Grant warmed up on the terrace for him from the start (think it kicked off at 10pm), then Carl got there about 11pm or just after and played the terrace while about midnight, they have to turn off the terrace then due to noise pollution.
As Carl comes to the end of his set Will Grant runs inside and plays for another hour and a half or so, really getting it going, then whoever the weekly guest is plays for another hour and a half, maybe 2 hours, then Carl finishes off the night. Either 3am til 6am, or 4am til 6am. Or a little later. One of the best nights IMO.