I've got my Stage 2 booked for the 14th December.
It's scheduled for 8:30 until 4pm, is this accurate?!
From what I can remember reading in this thread, Stage 2 lasts about that long, so yes, I think it is accurate. There are many computer tests to do. I don't know anything about the 'NATS computer tests', but when I did FEAST in Portugal, Part 1 lasted about 2 hours, maybe a bit more (3 exercises, 10 minute break, 3 exercises). FEAST-SDM (part 2) is longer: first a tutorial of 1h30m, then a 5 minute practice, finally a 40 minute test.
Good luck!