"Made like a gun, goes like a bullet"
So many Enfield stories. So little time!
Somehow I doubt the lady took her seat in this thing except to pose for the photo. Not a hugely dignified way to ride. I've read that hp at the time was computed by a formula that took into account only bore, not stroke. The formula was developed so that customers could roughly compare products, but, of course, it didn't do justice to any machine that had a long stroke. Only bore counted. When this same formula was then adopted for taxation it became a tax advantage to have a small bore/long stroke motor. So British motorcycles would tend to have a long stroke, and considerably more actual hp than the their taxed rating. Or so I get the story.