It seems that the Ac Comd was correct - he dropped CGS off at the specified grid - unfortunately, someone (ADC perhaps) had provided the wrong grid............doh
Infantry of all types don't like admitting they have mis-plotted a grid and so love to blame the aviators when they get dropped exactly where they asked but realise it wasn't where they really thought they should be...
As for crossing the border in NI - always amusing when the OC bollocks everyone for infringing it, promises trouble for the next offender and then does it himself
