Si Clik will be able to give you the answers.
Looking at the above discussion the RN only fly single seat fast jets thus the degree of difficulty should be the same as for the RAF single seaters ie only the best make it direct to SS, ergo RN FJ pilots are s**t hot.
Both RAF and RN Harrier jocks go to sea with JFH, the difference is that the RN guys WANT to go to sea whereas the RAF do not ie it is a state of mind.
What is more difficult? I suspect flying a Lynx to a Type 42 deck in sea state 6+ on a moonless, gloopy night, on min fuel and with a Hyd failure is more difficult!
Fly Navy!