Those who are doing the Stage 2, I can tell you that the ATC Knowledge test is fairly easy, just study that booklet and you will pass it for sure.
I recommend you to use public transportation as if there is any kind of congestion you will fail this stage... For example, today we were supposed to be 6, but due to an accident at the motorway, only 2 (me and another guy) got there. They delayed the assessment about 40 minutes but still there was no sign of them, so they continued without them and I'm unsure if they failed the assessment or if they can have another go....