I'm not speaking for the UK regulations, but in Canada for comparison sake, sorta yes. If you know your way around the paperwork system, such a thing can be paperworked to be legit.
Get the owner's consent.
If you want to intrude least on a Cessna, "obtain" an extra wing inspection panel - a sympathetic maintainer would be a good person to start with. Mount the camera to that panel, and ASK if you can replace an existing wing inspection panel for your flight. Chances are an "okay" will be close at hand. The aircraft owner will be more interested in how the pilot will fly with a camera aboard.....
My greater concern is how the aircraft is flown with the pilot knowing there is a video camera attached. "Watch this" and airplanes do not mix well. Consider very carefully how the pilot will continue to fly responsibly, and not "amp it up" for the camera - that's where the trouble begins.