I was going to ask why but just been on the website and found out
"While stocks last! Due to the impending warehouse move, hefty fit out costs of our new swanky fancy pants 2000 sq foot showroom - causing us a cash strapped credit crunch critical cashflow crisis - we are announcing our first...
That frame is a large not a medium so it should be 18"
the medium was 16" and had a bend in the top tube just before it joined the seat tube. I ride a medium and I'm 5' 11" so a large should be big enough if you're 6'