This appears to be the case on this forum but when you get to the festival and see the families, couples and others wandering around, particularly talking with people in the Kids Field or around the site, many of these people just logged in and were lucky enough to get a booking page that stuck.
We were 4 people going for tickets for a group of 5, another two trying to book for a group of 4. I would think that is a fairly typical situation for “semi-organised” people, and we got lucky. On Thursday for coaches we didn’t get a sniff. Swings and roundabouts?