I will definitely try this tomorrow.
All zones were assigned originally, but I still couldn't select to set Zone B when I entered the user code.
I definitely only have the one code as I tried deleting all users and trying again to no avail.
I've definitely done something wrong regarding zones. Do you mean zones as in A, B, C and D or zones as in Sensors?
I presume you mean A, B, C and D in which case, I have been into these and amended the parameters to what I want, but it still would not let me. I had A and B as full and part set respectively, and C and D as unused.
Thanks all for sticking with me through this, it's greatly appreciated!