Ha. ha!! As I thought, it says they had seen her HOLD a gun, no one mentions that she knew how to handle a gun or that she had ever fired one.
Holding a gun is the first step to firing one. You must have had Sheila down as a right idiot. She was brought up amongst the things,used to join in on shoots ( by even attending them in the first place ) .
Anyway,wasn't it DB who'd " recalled " that Sheila had,indeed,fired a shotgun on one of the trips to Scotland ? Tut tut,what a short memory.