If you go to 'Manage Bats' - press X (or whatever the button is for filter) it tells you how many you have.
View attachment 228050
You can do the same for logos.
View attachment 228051
I have a feeling that if you have high number of logos (e.g. using a lot of storage) it might start to limit the number of bats and/or stadiums you can have. If you compare to mine (the numbers are in those images) you might be able to see if it's more or less likely you have reached or are close to reaching the limit.
I still have the option to create bats. I only have 27 custom stadiums too, so that might factor into it.
Cheers buddy, much appreciated.