Yes, corresponding Standard and Ultra Heavy Duty closeboard panels have the same published width, height and 45mm depth. The Ultra version adds an extra 75 x 32mm backing rail rather than increasing the overall panel dimensions.
At the published product dimensions, yes. A corresponding Ultra Heavy Duty closeboard panel is the same overall size as the Standard version at that height, so the Ultra specification changes the internal support rather than making the panel wider or thicker.
For example, our 6ft Standard Closeboard Fence Panel and 6ft Ultra Heavy Duty Closeboard Fence Panel are both 1830mm wide, 1800mm high and 45mm deep. The Standard version uses four 75 x 32mm backing rails, while the Ultra uses five.
The additional rail also changes the listed weight. At 6ft high, the Standard panel is listed at 40kg and the Ultra at 45kg. The same principle applies at other heights: the equivalent Ultra panel keeps the same external dimensions but adds another backing rail.
This makes Ultra Heavy Duty a construction upgrade rather than a different bay size. For replacement work, still measure the actual opening between the existing posts before ordering because post positions can vary independently of the published panel dimensions. See all corresponding sizes under closeboard fence panels.