Possible need ?

At least must ensure that the operation makes sense with the new split-form attributes,
( i.e. using existing equalise code with the new 'cube.attributes' combined access approach : #4983 )

However, we may need to handle newly-possible collisions between matching local+global settings in a more intelligent way

• possibly provide automatic resolution of some such problems -- or detect + error/warn
• possibly add extra keywords to control different resolution modes