Who thought up the two (or more) silencers theory?
I always assumed that this theory originated in the silly era of 2004 - 2011, because it wasn't raised at the 2002 appeal, but if you read some of the statements from the 1991 City of London Police investigation, it is clear they were asked if there were other silencers or if a silencer (another silencer) was seized on the 7th August!