Sometimes statistics leave no room for caveats.  In the three general elections since 2007, Sinn Féin’s share of the first preference vote and its number of representatives in Dáil Eireann were on an upward curve.  In the 2020 contest, the first under Mary Lou McDonald as leader, Sinn Féin won 24.5 per cent of the first preference vote and 37 of the 160 Dáil seats.  If it is to repeat that performance in the next general election, it will have to return 40 deputies to the enlarged 174-member chamber.  Such a result – from a quarter of the first preference…