The Irish general election happens on Friday. In times past, observers would be marking the rise of Sinn Fein; now the interest has shifted to the parties that are challenging the political consensus. Irish politics can seem weirdly homogenous – with the main parties, in terms of culture, roughly equivalent to the Lib Dems and the wetter end of the Tory party, though in some respects (when it comes to wokery) similarities with the SNP spring to mind.