Bravo or delta?

Early start to work as it was A level results day. I volunteer to help in the clearing call centre that is set up in the library each year.  We had less space than last year and it was very noisy.  I took calls from 8.01 to 12.00 non-stop and was ready for a lunch break. The afternoon was slightly quieter but we did work until the hotline closed at 6pm. I was exhausted and had a headache from wearing heavy headphones all day.  
We have this phonetic alphabet cheat sheet as it can be difficult to hear and there's a world of difference in university places if you have a D rather than a B. Happy to take over 50 calls and make about 15 offers during the day.