surely another difference between the sides is that the English bowling attack seems to have more depth and variation than Australia's at the moment?

I can't buy that.

If McGrath was fully fit Australia would have a genuine quick, a Stathamly niggard, the world's best wrist spinner and a left armer bowling chinamen as well as a Hoggard like "why bother" bowler. England may have the advantage in having two genuine quicks but the convicts beat them all ends up for variety.