Boosey & Hawkes in from England. They probably order it from their supplier but they did not have it in stock so then the supplier had to order it from the Company which means a significantly longer wait. That's why it's "hella slow". It happened to me once because it was a difficult score to octain and it was printed in France.
Normally, if SheetMusicPlus has it in stock, I get it within 5 days because they are located across the bay.