The 2012 CCRC submission tried to prove the silencer was not used. This was by trying to prove Nevill's back was burnt minus the silencer.
This would just mean another item was used to burn Nevill's back. Or the silencer was taken off after Sheila was shot twice & then Nevill's back was burnt.
Besides which it was not possible to determine whether the burn marks were made with or without the silencer attached.
But good of Bamber to suggest Sheila was a calculated killer who could lift a 16 stone man in order to burn his back.