In our (USA) AARP Bulletin, there was an article by Betsy Towner listing 50 phrases that have been around for many years and what they really mean. Number 31 was "Off the hook" which she defined as "Crazy, like a ringing phone before voice mail". I grew up in Michigan in the 30's, 40's and 50's and that phrase had a different origin. It was a allusion to fishing and meant that, like the fish that somehow got off the hook, you had escaped something unpleasant. I wondered, seeing your website cited, whether the definitions she used were particular in some cases to the UK and not the USA.