The other thing to keep in mind with the upper/lower house thing is that usually when an election is held, it is for all lower house seats and half the upper house seats, providing some time lag for the Senate. Serves as a sort of partial safe guard against a parliament being driven by a large single issue.
Yet another contrast between Aus and UK is that we have state governments in between the Federal government and local government/councils. Interestingly, all states and territories currently have Labour governments whilst the Liberal/National coalition is dominant federally. Local council politics appears to be less influenced my party politics, 'though not totally devoid of it.
When it comes down to it, I'm fundamentally reticent to see a governemnt given total control over the legislative mechanism. No one government should ever be allowed to act without some sort of restraining mechanism - preferably chains and electro shock collars...
Regards,
Stuart.