I don't know if I can add anything that is not already on the internet. However, I do have in my collection an officially impressed Crimea Medal to a Sgt. Alban Elton RM, who received his medal while on HMS London.
After researching the man, what was interesting to me was that Elton was only on HMS London as a passenger, travelling back to England having served at Therpia Hospital. For his entire career he appears to have been carried as a supernumerary on nearly every ship he served on, which suggests that he had particular skills, over and above that of a Royal Marine that perhaps qualified him for working at Therpia.
Apart from the six nurses who travelled out to the Crimea with Mackenzie, I'm afraid I do not know how the Hospital was organised or run, but unlike Scutari in the early days of the war, being sent there was not a death sentance - infact the Navy managed to keep most of it's men healthy while serving ashore, and only the most seriously ill were ever sent there. If a man fell ill, or was only slightly wounded, he was generally sent back to his ship to convalesce.
On leaving the Navy Elton became a Sgt. Instructor with the 1st Battalion, Cornwall Rifle Volunteers, in Truro.