I've listened to two of these. The first I won't link to because it's a scenario I have in mind to run myself; the second is Dead Man Stomp, a 1920s Chicagoland jazz-oriented scenario in the CoC rulebook which is a neat story but is riddled with plot holes and very difficult to fit a typical party of pasty white CoC investigators into. 
So far, it's seemed like largely an exercise in frustration, leading me to wonder what, other than the classical British love for a rotten evening, is leading them to continue. Both scenarios, one an hour long and the other two hours long, have lurched stop-start-stop as the GM fumbles along reading straight out of the book, the players search desperately for a plot that seems to keep trying to kick them out, and then all hell breaks loose at the end and everybody dies. Believe it or not, there's also a recording of the complete Masks of Nyarlathotep campaign in an amazing 26 two-and-a-half hour episodes. I don't know if that's the same group, but honestly I'm not sure I can subject myself to it.
(The only reason I would, really, is that Masks of Nyarlathotep is generally hailed by fans and haters alike as being more or less the pinnacle of Call of Cthulhu, but is currently out of print and either costs $200+ from collector-gougers, or can be bought as a PDF from Chaosium for $25. That's ... pretty steep for a PDF. 0.o So I think it's gonna be a while before I can get ahold of a copy. But 65 hours of wandering around trying to find the storyline? Oh, honey, I dunno...)
Still, I suppose it's comforting to know that gamers across the pond are geeks as well.
 I found myself biting my tongue to avoid crying out at work when the players identified Louis Armstrong as the guy who played Baloo in The Jungle Book. Then they decided that he couldn't have played Baloo, so he must have played King Louie, which is only slightly less horribly wrong. In retrospect, it kinda fits the situation the characters were in, tho.