Given that Amanda and Raffaele are assumed to be innocent, they are surprising findings though, aren't they?
Hypothetically were those both to come back as legitimate they would interesting, but hardly evidence of murder in and of themselves. Consider the evidence against Guede in comparison. Off the top of my head there's the three instances of his DNA on Meredith's clothes, the DNA inside, the shoeprints all over the murder room and leading out the door, the DNA on the purse, the bloody handprint and his admission he was there when she was stabbed. Oh, and the dump in the toilet. That's a lot of corroborating evidence.
On the other hand the evidence in the murder room against Amanda amounts to 10 picograms of (we're assuming here) Meredith's DNA on a knife she used, thus bore her DNA, but with no traces of blood, doesn't match two of the wounds or the outline and was found in Raffaele's drawer, not the murder room. Much easier explanation than it being used in the murder thus implicating Amanda: she used it, cleaned it, and wiped it on her sleeve to dry it as she put it away; as she lived with Meredith something adhered to it from her sweatshirt.
What I find more interesting is that with all conditions considered anyone could think that knife was ever used in the murder just because they found 10 pg of Meredith's non-blood DNA on it. If they found a piece of paper with Amanda and Meredith's DNA on it would you assume it was proof of her being involved in the murder because it could have caused a cut on her hand and pulled it away real fast before it started bleeding?
If the Independent experts say that from their viewing of the evidence that this is their conclusion, I'd have to agree with them based on their evaluation of the evidence, unless there was good reason to reject their findings.
They may confirm that the DNA is Raffaele's, however while they have instructions to check the procedures used, it has been said in Italy that contamination has to be 'proven.' I'm not sure exactly what that means either, perhaps someone else can explain, but speculatively, let's assume it's something arcane (

) and virtually impossible to prove, (this is the hope of some of the guilt faction last I checked) and Italy's total lack of DNA standards whatsoever otherwise allows it in court.
What is it that makes you think that DNA being found on the clasp necessarily means Raffaele was in the room during the murder with absolutely nothing to corroborate his presence there? Having viewed the tape and all? Does that also prove the other two or so people whose DNA was also on the clasp were in there too?