Did not managed to finish interface. Still getting my head around Android Bluetooth - a few steps closer to dealing with input and output streams. Android Studio has feature rich debugging so hopefully will be out of the woods before the end of this month.
Other developments, will try to make a start on the circuit, printed some notes by Texas on laying out PCBs for high frequency devices. At low baud rates I am not sure my device falls into this category but I don't have the knowledge or tools to monitor the actual communication between the two Bluetooth radios so will work on the assumption it is.
Finally, I was thinking about bringing in Fritzing to document the actual Uno - BT0415 setup to make it easier to replicate in the future.