Buzzing noise from rear (of car) ?!

[Red-Eye]

Hi I've got a funny buzzing noise, possibly coming from the rear of my car ? It is usally there between 45 & 55mph in most gears.
Does anybody know what could be causing it? I did take a look under the car at the weekend but could not find much, all the exhaust brakets & rubbers are all ok. There is a lot of heat sheild & plastic aero shielding under the car, could it be that? I have also read about the prop shaft bearings seizing up, but that looked all ok, but is there way of checking?

It is a 56' 2.0TDi Quattro.

Cheers.

 

[TAC]

Fuel pump maybe?

 

[Red-Eye]

Had another check lastnight, it seems to be coming from the LH rear passenger side panel, any ideas what could be causing this noise, how easy is it to remove the side panels? FYI it's a 3dr. Cheers

 

[sean3794]

If its coming from inside the car it could be the rear
speakers these are amplified and can play up when loosely fitting or bad connections I've had this recently with the same kinda symptoms,the heat shield is more metallic sound! Hope this can help

 

[Red-Eye]

Cheers sean, Any idea how to remove the side panel, I've had a look & cant find any hiden screws or bolts ? If I did remove the side panel, would this effect the side airbag?