You cannot have it both ways that the Police thought it was suicide (which they did, and could have been right) and use that as an indicator of it being a valid view that suicide was convincing (which is was), THEN not accept that the silencer evidence which the police also bought into wasn't credible.
You're using the police judgment to back up the suicide credibility, but not use the same judgment with the silencer.
It wasn't really the police's initial judgment (based in Jeremy's account to them, and of their own view of the scene on entry) that caused the problems. It was the fact that they allowed this initial judgment to influence all that they did thereafter and 'skimp' out on the collection of evidence, cutting corners etc. However well intentioned it might have been (or ulterior) it was the gathering of evidence that made a mess of this case.
The repercussions of these mistakes became (and were also going to become) political, and it's THIS upon which I believe JB's strongest case lies. The Judge was aware of much of this mess at the trial, although, not aware of it all.
I don't think a court will change it's decision on new interpretations of the evidence that was presented at the time (unless it's of a magnitude way WAY beyond anything that's surfaced so far), but it MAY do if the scope of all the evidence that was LOST was quantifiable in an understandable way.
This is a crass illustration but:
If said there were 10 pieces of evidence supporting JB being guilty, and 5 supporting Sheila being guilty (just an example!!!!) then this can look quite bad for Jeremy.
If you know that 300 pieces of evidence were 'lost' as a result of the fiasco, then the the 10:5 balance no longer looks like he's twice as likely to be the killer - it look MUCH more like pure luck he got 10 and she got 5, but had the 300 been available, she might easily have overtaken Jeremy.
Like I said, not the best analogy but that's the reality of how much could have been lost in releasing the building back to the family after 2 days, and of not doing their jobs in those two days anyway!
The current strategy for JB's defence team isn't working (imo) and countless times 'new unearthed evidence' has proven to be discounted with aplomb.