All hail the mighty quattro!
Not too bad to get the bottle out. Had to take mine out the other week to take my ABS module off. Need to go through your arch liner. Jack her up, remove the million screws holding the liner in and pull that out the way, 2 bolts inside there holding the bottle and 1 inside the engine bay at the top. Then the 2 pumps just pull out. Unclip the connector blocks and hoses and with a bit of gentle persuasion she'll wiggle out. Easy job. Think mine's got a bit of a leak too, wasn't sealing too well around the lower pump, bit of cracking there. Bit of silicone'll sort that for now!