Online assessment followed by invitation to head office for a test in which you have to write what is being said and then switch to math questions, all within a time limit. After that, you get shown around the control room to get a feel for what it's like.

Go in for a test to see how you multitask under pressure, then a standard face to face interview - they help by giving you approx 10 mins to look at the questions they are going to ask you before coming back into the room for the interview - the process is friendly, but clear on the job’s difficulties and shift patterns.