British transports used in the Egyptian Campaign in 1882 carried their own unique registration number on the hull

All steamships employed by the British government as transports carried the Naval Reserve flag with a yellow anchor in the fly. They were numbered consecutively with their numbers painted on each bow and quarter. Steamships prepared in India for the Egyptian campaign had red figures on a white ground, the ones at England black figures on a white ground.

Source

Wadhams, U.S.N. lieutenant Albion V. "Transports. Egyptian campaign", Proceedings of the United States Naval Institute, volume VIII No. 4, p. 615. Annapolis, 1882.