Good advice above, thanks guys...! I'll detach the 1.4TC and just use it as a 150-600mm and see how I get on. I was mainly using single shot and not high-continious, I'm not sure on A-1 to be honest? Don't know much about it.........yet.
I'll try the 5-point group focus thanks. Seems too many options.
What do the Pro sports shooters use settings wise I wonder....(?)
Not a lot difference to what you use Peter - either single point or a small group AF (some swear by either)
AF-C continuous mode - frame rate in most cases docent really matter to much except in a few cases e.g. crash sequence.
Shutter speed depends on what your shooting - head on up to 1/800 a sec the only thing you need to watch is non slicks a fast shutter speed with treaded tyres will freeze the tread patterns and possibly make the shot a bit static (hope that makes sense).
Non head on shots somewhere around the 1/320th is a good starting point.
Aperture depends a lot what lens they are using - usually a stop or two down from wide open.
After that is practice and more practice.
The menu setting A1 controls when the camera will take a shot the continuous AF mode on the D810 you have 3 settings
Release - will take a picture regardless whether its in focus or not
Focus - will only take a picture when its in Focus (I've found that not to be case at times)
Release & Focus a cross between the two.
Using release will make the camera seem more responsive - probably will get more out of focus shorts though.
Focus will make the camera less responsive and at times it just won't take a shot.
Try both to see what you prefer, like I said personally I swear by release I had a few occasions when using focus when a really nice piece of action is occurring and pressing the shutter has had no effect and I would rather the camera took the picture (it might not be pin sharp but if its a rare occurrence I can put up with that.