We have already gone over this.
The narrative he used as the foundation of the defence on the silencer evidence, effectively confined the entire cross-examination of the prosecution's witnesses to the prosecution's terrain.
Hayward stated there was a "remote possibility" that the blood in the silencer was a mixture of blood from Nevill and Junes. Rivlin's strategy was to work Haywards own concession from "remote possibility" of mixture to "real possibility" essentially making the jury believe that blood had genuinely entered the silencer through the shooting, but arguing it was misidentified as Sheila's.
Hayward was a scientist who could only speak to what the blood tests showed. The relatives were the witnesses who where alleging how the silencer got to police in the condition it was in. In those circumstances any effective lawyer could question Hayward along the lines of "was this blood legitimately in the silencer at all, given who handled it before police collected it? and sooner or later elicit an answer along the lines of "I don't know".
You are confusing "the police" with a lone officer by the name of DS Jones.
Is there any robust evidence of the relatives contacting the police confirming they found the silencer with blood, paint, hair and scratch on it? Or did all this mysteriously come about when it fell into the hands of DS Jones? Please think about it very carefully without your usual knee jerk reaction...what robust evidence exists that the relatives contacted the police about the blood, paint, hair and scratch before it fell into the hands of DS Jones?
You are unable/unwilling to take on board the blood, paint, hair and scratch on the
outside of the silencer and the blood supposedly found
inside are fabrications carried out by different individuals at different times.