Mitch,
Yes it sends a shiver up your spine when you get reports like that - hail covering the ground! Hail, if falling prefusely, can accumulate rather quickly. What is amazing is this must have been close to pure hail as the storm was moving rather quickly as Harley suggested.
Radar did show some reasonably impressive echos off the coast of Sydney at the time of these storms approaching Engadine!
Regards,
Jimmy Deguara