Leave your tie at home and come in "business casual". Make sure your shoes are clean and shiny and your hair cut is up to date. Be yourself and enjoy the days at Luton. They are a great bunch of people there and always open for a good laugh. Be authentic and not too artificially "orange". As I said, be yourself. Either you fit or not.
All the best
FI
Would you rather suggest a "casual" dress code like they suggest on the letter of invitation to the interview or really a "business casual"?
There's quite some difference (jacket,shoes,etc)
Thanks
Bubair