Wrong assumption.

The battery I ordered arrived and was soon soldered into place but it certainly didn't fix my tablet, it became far worse. After checking things and re-soldering, things were still dire.
I then attacked the new battery and soldered directly to the terminals before they ran through the protection, and it's been splendid since. A lesson to be learned here, hopefully it's a case of the tablet already having charge protection and being a lost soul if it strikes another layer of protection, anyway the new battery (actually a cell but very few will get that) may have about double the capacity, which I may find useful sometime.