'01 156 v6 same problem as you guys. Been smelling petrol for a few years, mainly when the windows or sunroof are open and mainly in the cabin and boot, even after shutting off. My pump has already been sealed with some white hard plastic goo, but it's now cracked and leaking, and not just a little bit. Once the engine is off, the crack continues to ooze petrol as I'm guessing it's under pressure.
I'm going to try using Plumber's GOOP, a product from the US that takes 24 hrs. or more to harden, but it's been able to fix: a leaking propane fitting and a cracked PVC fitting on a swimming pool pump, so it's pretty tough stuff. I'll let you know if it works, otherwise it's a new pump assembly for the Bambina.
father of the Bambina