MrsSallyAdams is correct--in addition to "A British Subject" replacing "Ceylon", "A Private Investigation" replacing "Settling Up the Score", and rewritten confessions, the West End production also added "England Reigns" and cut "A Man Could Go Quite Mad" and "Moonfall (Quartet)". The currently licensed version of the show is the West End script, but with an appendix that allows you to swap those songs in and out. The West End version was also, I believe, the first to close the first act with "Off to the Races", moving "The Name of Love" to the second act, but that change is now permanent.
In his notes introducing the appendix, Rupert Holmes says the reason he wrote "A Private Investigation" is because "Settling Up the Score" uses the same melody as "Don't Quit While You're Ahead" and the two come too close to each other in the show to justify the re-use of material. Personally, I think "Settling Up the Score" is a much better song, and I am glad that Holmes allows the option to reinsert it.
