If you have PR and a parliament full of social democrats, then you are stuck with both, because the social democrats no longer need to win local support within each constituency. They just need the broad support of the population, and with their iron control of mass media this is never hard to arrange.
Now, I'm not convinced that there actually is an "iron control" of the mass media. It simply isn't necessary that there should be. And I think most journalists and editors and proprietors would be indignant that anyone questioned their independence. (Editors may not be entirely independent of their proprietors and journalists may not be entirely independent of their editors, but that's a different matter -- I'm talking about whether the Conservative or Labour Party "directs" the media one way or the other.)
What actually exists in the media is a complete lack of critical analysis of the underpinnings of our society. In other words, the media is filled to the brim with people who have bought in to the cozy consensus, completely.
There is a general acceptance that some form of social democracy is the way forward. While some people think that government should do things better or smarter or more, there is never any question that the government should do something. Anybody who does so is swiftly dismissed as a tin-foil-hatter or some other disparaging description.
Nobody really wants to think too hard about how you underpin society. And very few people like taking complete ownership of their lives, which is why social democracy is so popular.
It's all a question of perspective. To a hard-core Labour voter, Tory policies are awful. The slightest dent in the low of the fountain of state money is a pernicious evil. To a libertarian, there is such a minor difference between them that you might as well vote for one or the other by flipping a coin. A libertarian has a completely different frame of reference.
If you want to change that "Islington mindset", you need to keep challenging the foundations of those beliefs. Write to the papers, or the BBC or whoever, introducing small challenges to make readers think. Don't rant or rage (that's what blogs are for!) but just chip away at the foundation set of beliefs. If this happens in sufficient numbers, from a sufficiently large number of readers, we can maybe get newspapers to challenge their base assumptions.
And that's how that apparent "iron control of the media" will begin to crack.