My 11 month old Volkswagen Golf GT 1.4 DSG has for several months had an intermittent rattle from the engine. It is more audible from the passenger side but this may be due to the sound bouncing back of roadside walls etc (and the fact that the driver is slightly deaf!).

The noise appears to begin when the engine is beginning to accelerate and can diminish under lighter engine load. Lifting the foot off the accelerator makes it disappear altogether. It doesn't vary with either road speed or engine speed. I have reported it to my dealer when it first occurred and again at its annual service but on neither occasion was it possible to recreate the noise whilst there. Have you any ideas on what this may be please?