I spoke with tha CAA IREs at the time of that policy change and they told me that AL failure would be assessed by oral questioning in future MPA IRs.... I described how we trained for it in the RAF VC10 simulators following the Korean 747 crash at STN and they were more than happy that we were taking such a proactive stance!
But the fact remains that holders of UK CPLs never need to revalidate IMC Ratings, whereas holders of UK-issued JAR-FCL CPLs currently do even though they may have a current MPA IR.......