Hi,
You can put a breakpoint in class CL_EXITHANDLER, method get_instance just before opening the transaction on the Web UI. The breakpoint will hit everytime a BADI exit is instantiated in the course of the screen processing. You will be able to narrow down.
There is a variable called "instance" in the class. Check for the exit names where instance is not initial, those are the BADI implementations getting called in your system.
Hope this helps.
Regards,
Parul