This one would have not made the first culling in lightroom when picking my photos to send to the editor. To me the action is where the ball is in this photo and that is totally out of focus. Even the player at the back who I assume will be getting the pass is not in the focal plane. It appears to be in front of him. I'm not sure if the exif data is correct that you have uploaded, however 50MM is not something I'd attempt any field sport with and F1.4 isn't either. Especially not in daylight when I can get 200ISO.
So glad you went for this one Clive - it strikes me now as I look at it how Classical it looks - like an Old School painting, with the precise placement of the figures in the scene in iconic and almost tragedy-conveying poses. The Passion of Rugby.
Looks like you've done a lot of sharpening to this which is giving little halos around people. Try increasing your ISO (your camera can handle 800 or more without much noise) so you can get your shutter faster.