Well, i speak from expensive experience then..... It is most likely the DMF. Mine did the same thing at 59,000 miles and i then had a new clutch and DMF (recon DMF - have you seen the prices of new DMF's for a 20v!!!)
Now 6 months ago at 94,000 its happening again - this time i have left it. So far its done another 6,000 miles and is obviously still rattling (but still functions - no vibration or anything, drives fine, changes gear fine) - im just going to leave it for longer still as replacing it every 40-60k is expensive and if i can get extra mileage out of each one then all well and good.
Same noises you are getting - this time and last time. So i'd guess its the DMF. How soon it needs doing is a million dollar question - I have researched this question a lot. On a Volvo forum some guy did 60,000 more miles on a rattling DMF with no ill affects and still hadn't changed it! But don't take that as me saying it's ok - I'm just passing on what I have read.
The more i look at 20v's, the more evidence I find that they have an appetite for eating their DMF's. Some people are lucky, but most are needing replacement and not just after high miles either. You only had to look on ebay and they are coming up for sale there very often with rattling DMF's. That said I think the 20v is a wonderful car and wouldnt let this issue put me off......
I also know 'how' to drive with sympathy towards the DMF - and in my case it hasn't helped.
Last edited by j300sjl; 10-06-14 at 12:16.