Thanks for your responses. I've just learned something.
It's hard to get a feel for another country's politics sometimes. Voting FF or FG, it seems, has quite complex social meanings. I remember someone trying to explain to me why people voted for the various virtually identical parties in Belgium, and I had similar problems. It isn't simple left/right there either.
Would I be right to say that the word 'conservative' means something different in Ireland from Britain – something less pro-business?
Also (sorry for all the questions), I presume Sinn Fein voters are left-wing broadly speaking. Why are people voting for them rather than the Socialist or Labour parties?