Identify Jessica Biel's Movie Motorcycle: "Easy Virtue"

Can you identify this bike? I ran across this 1930s period movie, "Easy Virtue" last night and got a smile ear-to-ear when my eyes beheld one of the most appealing things in the world. Jessica Biel, in leather and goggles tearing across the English countryside on a vintage British motorcycle.

The movie could have been only that, over and over, and I would have paid full admission!