I think it depends - lately those that have gone through to Stage 2 have got an email.
Regarding the aptitude tests - I am through to Stage 2 - I remember doing the Reasoning test and the Wombat test at S1. I gather the Maths test and the stick 'n rudder stuff is up next ...
For those doing the Wombat test ... I must admit, I actually enjoyed the test very much indeed! I'd love to do it again - and this is a person who owns ZERO computer games .... it's actually fun