I applied online, with a CV + cover letter.
The next step was a 15-minute phone interview, where they asked standard questions:
"Why here"/"Why this job" and also about social issues/ social projects (they're big on this!!).
However, there was a massive echo in their room, so I could hear what I was saying repeated about 2 seconds later, which was tremendously off-putting.
Also, they said I couldn't start until March, when their website had said January, and it turns out their training is in Pune, India, which the website doesn't tell you (it mentions ThoughtWorks University/TWU, but doesn't mention a location, so I assumed it was London or Europe).
Overall, the job looked okay, but the process was so bad for me.