I first heard about FDM via email. I applied and on same day heard back from them, saying I should call them back to arrange telephone interview.
Telephone interview - was not too long, relatively easy questions. Passed.
Programmer aptitude test - this is not assessed. It consists of three parts. Maximum time limit of 65 mins.
Assessment centre - introduction to FDM by one of the senior staff. Followed by a video giving more information and a talk about the contract. Afterwards there were 3, 5 minute interviews. Then a test on Venn Diagrams followed by Lunch, you can go out for Lunch and have to return by 1. After Lunch there is a tour of the office, you see where the sales, recruitment and HR team work. After this there is a test which tests both your logical reasoning and general IT knowledge, lasts an hour. The third and last test is based on maths, lasts half an hour.
If you want to pass the tests practice some programming and also online logical reasoning tests.