Wow, you've certainly maxxed the shape from the cleft, an absolute beast of a bat.....
I still have a spare handle here for you, let me know if you still want it.
The chunk missing is the bark, the cleft has been cut tight to the outside of the split and a little has been left behind and then fallen out, I did have a beauty made with a huge groove similar to a scoop with moss growing on the bark, sadly when it was left for sanding someone thought that it had been left in the back by mistake and binned the bat.