Oz, AQIS manages it, here is a link to their info.http://www.daff.gov.au/aqis/export/meat/elmer-3/eucas
Your weights are good, bearing in mind you are calving about 6 weeks later than me. Like you, our summer pasture does not get going untill well into October. If the clover doesn't happen, Sept/October can be our toughest months. As I said previously the calves that sell for the headline prices at the weaner sales are a lot older and often EU accredited. Still at the weight you are selling, your calves should be very popular, your cents/kg should be pretty good. My preference so far has been to sell at liveweight sales, you get paid for the weight. The feature weaner sales that sell on a per head basis are good for the well known lines of cattle that regular buyers chase, but the lesser known vendors don't get the same interest.
As far as your problem with a heifer bull. The injuries you have had, I think are a bit of bad luck. For your 40 heifers, a 2yr old bull would be a little overworked, but I am sure he would get through them allright. By joining time they should all be over 300kg and should handle a 700-800kg 2yr bull ok.
I have a small herd of 40 females, when I have bought an Angus bull, I always go middle of the road for birthweight, I aim for +5kg birthweight EBV, I don't like them to be too far behind the eightball to start with. As long as the bull has both parents around that figure and not one at 8.5 and one at 2.5 to get the 5 average, that could be looking for trouble. Having a small herd the one bull has to do all and to date I have not had any trouble with heifers calving. Nowadays I am inseminating my registered cows and keeping a few bulls to sell so I have a few to chose from for my commercial cows and to use as clean up bull.