Tony just a stab in the dark here !!
Are you sure the Tiny chip didn't fall out perhaps when you had a look inside Keyfob?
If not perhaps swap the Transponder chips around between the 2 keys you have, and the "fault" should swap over to the new key.
Have you tried disconnecting Vehicle battery for 15 mins or so as the decaying charge on an old battery can make ECU's & BCU's behave in strange ways until a Power reset is implemented.