In Season 5, Amy has a prologue that only exists in syndicated versions and isn't present in the original UK airings. It doesn't appear on home media (DVD) either.
Season 8 in Australia is PG on television, and M on DVD. Science fiction themes and violence being the reason.
When shown on Disney XD, some censorship is performed: spoken instances of the word "hell" are muted and the printed word is blurred when visible in its entirety, but not when it is partially obscured.