Before making a joint committee application the principal councils must consult—
(a)local people in the principal councils' areas,
(b)each of the councils for communities in the principal councils' areas,
(c)the National Park authority for a National Park, any part of which is in the area of any of the principal councils,
(d)the public services board or boards for the principal councils' areas,
(e)every trade union which is recognised (within the meaning of the Trade Union and Labour Relations (Consolidation) Act 1992 (c. 52)) by one or more of the principal councils, and
(f)such other persons as the principal councils consider appropriate.