Dyson Retail Technical Designer interview questions

First interview was meet and greet. This part of the process went very well and the interview panel were interested and easy going - it felt fairly informal. Second interview was a technical project which involved being given a written brief which asked you to draw up a retail display unit to be fitted in a shop. The display unit was drawn up to concept level (PDF visual presentation with some rough descriptions of what the unit did, how it worked and what it was for) and as a technical designer you were tasked with developing and detailing the concept ready for manufacture. You could use any software and had to output a PDF presentation or set of drawings. I put a lot of time into my submission but unfortunately, didn't get invited back for a third interview to discuss my submission. This was a real shame but I know that I made an error in my chosen direction early in the process and by the time I realised it I didn't have time to correct it (too much rework) due to commitments at my existing job. Overall the interview process was professional and the people I dealt with were pleasant and easy going. Frustrating that I didn't get the opportunity to talk through my submission but I know the early error and the lack of time to fix it was a big part of this.