Well you said : "Numbers must not be repeated or missed out; so it's 1; 1,2,3; 1,2,3,4,5; however many. "
For me they are in order :p
If you don't care about the order, just add the condition of the previous box to the where.
So
where Daig_number <> DAIG_1 for the second box
where DIAG_number...