I'm not sure if its the aptitude testing and interview you are talking about? I went through the selection process just under a year ago.
Basically, after you complete the OPQ questionnaire (apparently only around 33% get through it), you are invited to complete 5 aptitude tests. Examples of these tests are found on the Airways website. You have to pass all 5 of these to proceed.
There is a short 15min interview after the 5 tests involving questions such as what do Airways do, what is your level of involvement in the aviation industry (I said enthusiast), etc etc. You then get invited to the assessment centre.
Hope this helps? If not, just ask.