I think I've found the problem

After randomly reading up on reconditioning of flywheels, I see that a lot of people are complaining about dual mass flywheels (various brands). The flywheel lose the tension in the springs (or break) so you can end up having a few degrees of slack here.
I went outside, put the car in 1st gear and had a mate push and pull the car while I was lying under it. The noise comes from the rear of the engine/bellhousing. Putting it in a higher gear didn't change the noise, but the car could move a fair bit more before it hit the "clunk".
I can't conclude before I take off my gearbox and try to shake the flywheel, but everything I can think of proves this, it seems logic. After all, the flywheel has been used/abused since 1995, have at least 137k miles worth of road and as I know been mounted on 4 different engines..
So, IF my DMF is fubar, how on earth do I get a new one? This is not an item you usually would transport across borders due to weight
