timing belt noise 200tdi

The last few weeks there has been a noise coming from the front of my 200 tdi motor. The noise sounds just like a belt slipping or rubbing so I though it must be either the power steering belt or the alternator belt but I took both of them off and it still made the same noise with no change. this has lead me to belive it must be the timing belt as that is the only other belt how ever I know it cant be slipping because its got teeth. The timing belt and tensioner are new as of 10 000 kms/ 6 months. I have already taken the timing case off and every thing looks normal apart from the belt seemed to me right up at the front edge of the tensioner and looked like it could be rubbing on lip of the edge of it so I set it back a bit and it seemed to stop the noise for a bit but now it is back. the noise only starts after running for a round 3 minutes form cold. does anyone know what could be wrong or knows what's happening ???
thanks advances

Belt to tight?
Defender or disco engine?
Could also be tensioner or idler if disco pulley worn, for the cost and whilst you are in there I would change the lot.
Recent post on here where guys camshaft pulley bolt cam loose, might be worth checking its tight?

its a disco engine but every thing is changed over so the only thing that is from the disco is the block and the head.
The timing belt has done about 10 000 km and for the first 6 000 it was fine it has only has started making the noise in the last 4 000 km, is it possible that the belt has tightened ?
I did see that post and when I took the timing case cover off the last time it didn't appare to be lose or not to the extent as that guys, but I will check again.
thanks

Is your water pump on the way out? I had a noise in that area and it was a matter of days before the water pump gave way.

To be sure -

(i only know 300s, so forgive me if it makes no sense)

There's a lip on either the crank sprocket or the idler, right? If neither have a lip (which is possible with a mis match of parts on the 300) then the belt will wander.