It seems to me that pretty much any electoral system is going to give roughly the same results. It would be nice to get the money out of politics if you could, but that is not very likely...
A proportional system, with more than two significant parties, would give very different results to a first past the post system. It is up to the voters if there are more than two significant parties. Malta for example manages to combine a two party system with proportional representation.
The Australian system ensures that each electorate gives majority support to its representative. It is thus fairer at the the level of the individual seat. However the overall result may be more distorted than in a first past the post election.
In any non-proportional election system if party A wins large numbers of votes in its strong areas, whilst party B ekes out a lot of narrow victories; it is possible for the party with fewer votes to win control of the House. This happened in the UK in 1951.
The only reason I suggested a preferential system in single office elections was to keep as close as possible to the existing system.
I know that UK MPs are strongly attached to the idea of single member constituencies. This is a wrong end of the telescope effect. Because MPs like being the unchallenged local bigwig and the single member constituency is important to them, they think it is important to the electorate. Experience of multi-member local government wards and the additional member systems in Scotland and Wales strongly suggest the voters do not care.
