You put a 1 by your first choice, 2 by your second choice and so on for as many as you want. They count the votes and if nobody has 50% of the votes the candidate with the least votes has all the second choices on his papers allocated to the relevant candidates, this goes on and on until 1 person has 50% of the votes. That is why your third or fouth choice can win the seat
Once he has come last - yes
If no-one still has 50% the person who is now last has their 2nd choices allocated to the relevant candidate, and if any of the previous losers votes went to him their third choice is allocated to the relevant candidate.
As we are not obliged to grade more than one candidate, and if , in theory, everyone did that (i.e no 2,3,4 etc) how would the contest be decided - first past the post I suppose?
Your first vote counts first - that's the one they look at first. If the person getting the most votes doesn't get more than 50% of the votes, then they add in people's No. 2 votes - and so on. It'll be hugely expensive to administer if it goes through, and there is nothing wrong with the current system. I'm voting against it.
I think it is the same as proportional representation. It is use in Ireland. You can choose your preference for all the candidates from your main choice to your second, third and so on. It is probably fairer than first past the post.
I was in Oz when there was an election and they use a similar system there I think. There was a hooha about the system not working at the time and people were calling for it to be abolished. I`ve voted No.