Has anyone asked themselves why Jeremy wanted the silencer tested again? If he was guilty then surely this would be the last thing that he would have wanted? Abit like the relatives not wanting everything under PII to be released? 
He didn't, the prosecution took it upon themselves to do so in order to respond to Websters expert opinion for the defence at the 2002 appeal.
Your comment regarding what the 'relatives' want, is unfounded, it may or may not be the case, but as far as I am aware, they have not shared any such view, either for or against. I guess the closest thing to it is Davids comments at the end of the recently aired documentary.