If you have a fuel smell in the cargo area, in addition to checking the transfer tubes take a look at the torque settings of the screws in the suspension plate in the top of the lower blader; where the bladder top is attached to the lower cargo floor. I don't mean the torque settings of the two bolts through the cargo floor.
If the screws are over-torques then the inner-bladder and outer-bladder metal plates can distort downwards in the centre and ease their edge-grip on the fuel bladder, and fuel can weep as a result. This would be more noticable when fuel quantity exceeds the volume of the lower bladder (about +240 KG? someone can correct me if that figure is wrong, I don't have the manual with me just now)