Thanks mate. Yeah, I am a bit reluctant to bore everyone with my family photos, but I know a few guys have bought these lenses lately so thought I'd post more for the lens than the family.
It's really surprising how close you have to get for these shots. That one with Ella jumping off the sand, first couple of shots I was maybe 2m away and she was practically a spec in the shot. I really needed to get right under here about a metre away or closer to make it work, and camera practically on the sand.
The shot with Hayden running was similar. I was actually running alongside him, hunched over with camera nearly on the sand, yelling at him to look at the camera.

must've looked quite a site for spectators.