The role was advertised by recruiters only, with a long list of potential job titles, but clearly wasn't what any other company would consider as Technical Director, since it was tied to just one client. It sounded interesting nonetheless.
The first interview was fairly unexciting, just covering the basics of personality and fit. One of the two interviewers was intentionally confrontational, but no-one asked anything deep enough to determine technical aptitude or depth of knowledge.
After a successful first interview, they set the most ridiculous programming assignment any interview has ever seen: architecting and implementing a REST API for potentially long-running asynchronous operations, comprehensively documented, and with some interface to test it. There was no deadline, because they wanted something that was "a true reflection" of ability. This company clearly places very little value on the time of its prospectively employees.
I spent evenings during the next week on their assignment, emailed the code, and a week later was told they'd already found someone. Apparently my "code was fine", and that's all the feedback they gave.