It will be the orange drains in the trans tunnel, link
here but this is for an American left hand drive car, so you dont need to remove the throttle stop etc, probably best doing them both but getting the drivers side off and on is a right PITA, amazing how much water collects in there, I even had it coming out of the vents in the rear, and you could hear it sloshing around, I actually took my drains out but you will need to cut the sound deadening stuff around them to get them back in, just use a Stanley knife to cut enough to get your fingers in then stick it back with D/S carpet tape. Be careful if you stick anything into the orange drains, I managed to puncture one and they are £22 from Audi, good luck!!