the first process is the online application form. there is a facebook site that gives very good hints and tips, use them. i answered the 3 questions online and 2 weeks later i was asked to complete a situational Judgement test. the test are pretty easy once you practice.
after that stage i was asked to complete a basic numerical test, then a mechanical comprehension (just a test on mechanical principles based on pictures and diagrams). after this stage i went through to the diagrammatic online test (which was the hardest art of the stage in my opinion)
i was then invited to attend the assessment center. a very relaxed environment. i had to produce my exam certificates and ID. then i went on to do a one to one interview, where they asked me to give examples of different situations and show how competent i would be for my role. then a group exercise. there was 3 other people in my group, all applying for different roles in different areas. then i completed a paper test, they called it a technical understanding test. it was more of a verbal reasoning test. you are given a chapter to read and you answer the questions relating to the chapter. very easy
two weeks later i had a phone call saying i was accepted.