Double jeopardy was abolished by Blair in the Criminal Justice Act 2003, Scotland abolished it as well a bit later in Double Jeopardy Act 2011. However i doubt it would apply even if we had it as the wording in Section 49 is so poor it could just be reissued as a new offense each time.

Has it happened? Section 49 of the Regulation of Investigatory Powers Act 2000 has a secrecy requirement built into it, where if you tell anyone that you have been issued a Section 49 you can get an additional 5 years (treated as a separate crime). This, as you can imagine, makes your question difficult to answer.

It does and of course it's different happened. My pet peeve has to be the "it's a poorly worded law" argument about things that have obviously been considered by legal experts. The scares like "the psychoactive substances act will technically make coffee illegal" I've seen on HN are particularly egregious.