Hey Frenchy,
Well that surface is pretty bad, so it leads me to believe you can take some liberties with it? If it is some type of bad product from a 3d scanner that needs to be "exactly like that" then this may not work for you.

But, you CAN get a result by running a plane down the center of the object and intersecting curves. Take one half of that result and offset it, then revolve them and do the Boolean to get something like this:



But this DOES deviate from the other surface, which has some detail that differs in the quadrants....