It seems too much time has passed to make an edit so here it is again.
Correction to the above:
The new keypad address is set to '3'.
The existing keypads are set to 0, 1 and 2.
In menu 60, when I check the keypad comms, keypads 0,2 and 3 show up as 100%.
The exisiting 0,1, and 2 keypads are all functioning correctly, however. Just the new '3' keypad is non-functional.
Is there something that needs to be set to correctly recognise all keypads?
The keypad that is now set to 1 was originally set to 3 and I changed it so that I could have the new keypad be '3' as it made more sense from a location point of view.
It seems as if the Galaxy hasn't picked up the address change from 3 to 1 of the existing keypad and is not detecting the new keypad now that it is set to 3.
Does that make sense?