Complex sentence: Some changes were necessary to the two brigades, as 5 Brigade had only three-quarters of 4 Brigade's personnel and equipment with the support organizations held at the divisional level.
Split into simpler sentences: Some changes were necessary to the two brigades, as 5 Brigade had only three-quarters of 4 Brigade's personnel and equipment. As finally envisaged, the division would have had two brigades as its fighting formations, with the support organizations held at the divisional level.