Ah, that's my old brain equating "publishing" with something on paper!
I believe a lot of the info from the London Gazette is already online, but in the past I have found it very difficult to search the archives. In recent years I have left this to a chum who seems to know the system better than I do and is willing to help out occasionally. There are also professional researchers who do this sort of work at the National Archive (formerly known as the Public Records Office). Some of them are very reasonable - others not so!