The RMLI would not have worn the red jackets in the Zulu War, nor the decorative helmets.
The following information was taken from Ian Knight’s “British Forces in Zululand 1879”.
Royal Marine Light Infantry on active service in Zululand wore dark blue working jackets. The jacket had four brass buttons down the front, with two small buttons retaining twisted scarlet shoulder cords. Collar badges were an embroidered red bugle. Rank chevrons, which were worn on both sleeves, were gold for senior sergeants and red worsted for below. Trousers were dark blue with a narrow red stripe. RMLI wore the Glengarry cap with regimental badge. The regulation white helmet (probably stained) was worn in the field. Leggings were black. RMLI carried the Martini Henry rifle with the infantry sergeants’ pattern sword bayonet (not the navy cutlass bayonet).
Royal Marine Artillery uniforms were similar. The jacket buttons were a different pattern than the RMLI and the collar badges were a grenade instead of the bugle. RMA trousers had a wide red stripe vs. RMLI's narrow stripe. RMA members wore forage caps with a yellow band for the men and a gold band for sergeants. As with the RMLI they wore the helmet while in action.
Contemporary photographs of HMS Active naval brigade show the marines in the white helmet; while those of HMS Tenedos show the RMLI in their glengarries and the RMA in forage caps.
Petty Officer Tom