The thing about the site office theory, though, is that they have a backstage area right next to Nemesis that they could use without doing any demolition; the access road to it leads right down past the extended queue line, and I believe the gate accessing the access road is right next to the Nemesis entrance, correct me if I’m wrong.
They also have a big car park not far away. And another one that looks directly onto the Nemesis site (although that one admittedly facilitates the walking route to the park, so I’m not sure they’d want to block that off).
My point is that there are plenty of alternative spaces where site office space could go. With that in mind, I’d be surprised if they’re paying for Sub Terra demolition to accommodate site offices and access when they could quite easily place that somewhere else for free.
My thought is that this is most certainly an exciting development, and does add considerable credence to the theory that Sub Terra is returning for next year. They haven’t touched the queue for the past 7 years, so why suddenly remove a load of wood now if you weren’t planning on using the space for something or other?