I am currently using a nested if statement similar to the one listed below,
although I have changed the cell references and removed all the $ symbols for
clarity, in a validation list.

=IF(A1=AA1,AB1:AZ1,IF(A1=AA2,AB2:AZ2,IF(A1=AA3,AB3 :AZ3,IF(A1=AA4,AB4:AZ4,IF(A1=AA5,AB5:AZ5,IF(A1=AA6 ,AB6:AZ6,IF(A1=AA7,AB7:AZ7,IF(A1=AA8,AB8:AZ8,""))) )))))

It works very well as depending on which of the 8 values AA1:AA8 is in the
reference cell A1 a different validation list is made available.

The problem is that I need to expand this to 14 variables instead of the
current 8.

I thought I had a solution when I decided to try putting the above equation
in one cell, a second equation covering the additional values in another cell
and tried to get the validation list to look at them both using the equation
"=IF(Equation1="",Equation2,"") but it equates to an error.

I have read through as many relevant posts as I could find on here and cant
find a solution apart from waiting for Office12.