Welcome to the forum.
There are few photographs of naval officers from the Zulu War. The only Commander I have seen is Commander Campbell, HMS Active. There is one of him with the blue jacket, white pants, and officer cap. The second photo of him is right after he was promoted to Captain. He and the other officers are all wearing blue jacket and blue pants. Some officers have caps and others helmets. Campbell wears, or holds a cap in both of the photos. I have not seen him with a helmet. The belt buckle would be the same on the undress uniform for commanders and other officer ranks below admiral. I can’t remember if the buttons were the same, but I think they were.
I don’t know what uniform was worn by the other two commanders (Romilly, “Boadicea” and Brackenbury, “Shah”) since I cannot find a photo of either of them. Some of their lieutenants and surgeon were photographed with the blue jacket and pants, with dyed helmet.
I think there are some photographs somewhere on the forum, but I am not sure where, and I can’t post any photos myself.
Below is the” Uniform Regulation for Officers, Petty Officers and Seamen of the Fleet” from 1879
I hope this is of some help to you.
Petty Officer Tom