Got flashed doing 51 through a 50

Going under a 50 sign on motorway gantry and camera flashed me. When I checked my speedo it said 51, I have dash cam footage that shows speed was 51. I know they won’t take dash cam speed as concrete evidence, but this is bullshit isn’t it? Has anyone had experience with an appeal actually working? Happened today so nothing has come through yet obviously.

Edit: I’m aware 51 is over the limit and I’m not claiming to be innocent, just don’t think it’s ticket-worthy as surely the machine has its own tolerances that this would be within. This was on the M62.