I sheared a nut that holds the stabilier bar in place.
Still, the battery seemed to take the overnight charge well and we are up and running. Now to go shopping...great.
Why do they corrode like that?
Because you don't do what sensible people do. If you live anywhere close to the sea, salt corrosion will occur. Cover all terminals, nuts, bolts etc associated with the battery with vaseline and I mean smother it on and repeat every time the vehicle is serviced.
As for TMR I would have the battery checked. It should not go flat through none use in three weeks. Mine has never gone flat despite being left in the garage for up to three months without use. Are you sure you didn't leave an interior light on or something? If you are sure then GET THE BATTERY CHECKED. Chances are you need a new one and winter is no time to find that out.