Mpplp,
The process has changed a little since I went through application, but it took around 10 days to be invited through to stage two. However, that was without the online personality test. I can't imagine that would delay the process too much! It's around a 3 month process all in all from initial testing to completion of medical; at least it was for me!
By the way, there are much better places to improve your sex life than job interviews! Tut tut!