chuffing belt noise

[micktheshed78]

2003, 1.6, 8v auto, 94K miles. I have a chuffing noise from the area of the belts, this has got worse over a few months but can only be heard when the engine is warmed-up. 

I've run the engine with auxiliary belt removed & noise had disappeared: but this may be because the engine had cooled down, as there was still no noise when refitted. There were no bearing noises from the alternator, tesioner or A/C compressor. Upon running for a few miles the noise returned.......dohhh!!!

As far as I can see the timing belt is OK, it's only 3 years & 9K miles old & the tensioner, water pump & thermostat were all renewed. Wish I'd done it myself now.

Any ideas? I'm trying to avoid a major strip-down that might prove pointless.

Any ideas?