I don't know what the problem is. The BBC reported it wrongly, stating that the change would mean 55% of votes would be needed to carry a vote of no cofidence against the government.

This bill would mean that the prime minister can't decide on his own when to dissolve parliament. He would need 55% of MPs to agree. This is a mechanism for making a fixed parliament exactly that.

In the Scottish parliament it's more like two thirds of MPs needed to dissolve. Far from being undemocratic, it's more 'democratic'.