The agency send me a technical test to do at home. The task was to create a Java program for the specification they provided (they said allow 0.5 day). They offered a face to face interview almost immediately after my submission.
The face to face interview consisted of 3 phases:
1) Programming test on their laptop/IDE
2) Technical interview with lead developer
3) General chat with the project manager and programme manager
The interview seemed to go fairly well.
Frustratingly the agency said they were not able to obtain any response from the client. Two weeks after the interview all I heard they had offered the role to another candidate. It had left me in an awkward position since I had other opportunities that were waiting on my response.