It's very funny when a number-based band have less than the required members. I remember seeing S Club 3 at a pride event years ago. You could potentially have two distinct S Club 3's knocking around.
It does say 'Super Early Bird tickets only available in a limited amount' - sounds like they might be trying to incorporate some kind of dynamic pricing to day tickets. 'Cos we know how much everyone LOVES that model of ticket pricing!