leaking

E93 (Convertible) With water in battery tray We have an E93 that began having a starting problem and we found the battery tray full of water. The cable to the starter had corroded so bad it broke off as soon as we moved it around. With the cable fixed, any thoughts on where this much water...

So found this explanation ... wondering if we can access this from inside the car when the GWS is removed ? https://bmwtechnician.com/2016/04/14/dct-trans-leak/ Also, given the number of gaskets that leak should we look at venting?