a noisy (well scratchy) drum in a Miele?

I have a Novotronic W 919 wps.It is over 10years old but now the drum seems to stick a bit.It doesn't seem to stop it from revolving and the resistance is very small and entirely evenly spread throughout the rotation.
I know the noise you get when something is stuck in the drum and it is not that.At a guess I would wonder if a coiled spring could have come loose and be causing this scratchy sound.
So my question is whether to be alarmed that this is going to get worse and whether getting in the service man is recommended now.
I imagine it would be a little foolhardy for me to start taking it apart myself.....