Well, it's the Henley Regatta. I know that because that's the title of the film, and it involves something to do with boats: long boats with lots of people pulling on oars ( two sets), and a bunch of people standing around in formal summer wear watching them, except for one guy in a boat watching the camera, as if he's worried the cameraman will do something dire. Because this is a very big sporting event. Can't have this bloody Yank mucking it up. What? He's actually British? Yes, well, he's wearing the wrong tie or something.
I am told that once upon a time, one of the questions on the Binet IQ test was to name everything needed for a regatta. That's probably why my relatives don't listen to me.