It had the makings of a checkmate win for PwC. Last year, the Supreme Court granted the big four accountancy firm a security for costs order against Quinn Insurance, the insolvent insurer that collapsed in 2010 with a €1.1 billion black hole in its finances. The ruling meant that if the administrators of QIL couldn’t come up with around €30 million upfront, there was a risk they would have to abandon their €800 million plus negligence claim against former auditors PwC over its alleged failure to raise red flags on the insurer’s financial statements between 2005 and 2008.  PwC, which…