I've actually seen a few of the older BBC adaptations of these and liked them(the actor's name and titles escape me, though.) Though I'm sure they were very stripped down versions of the book, they had some brilliant social commentary on the British upper class at the time, rather like Gosford Park(I believe someone told me once that these books were among the influences for that.) Sadly, I discovered them just as I was ending a masive mystery binge, and haven't been in the mood for mass series catch up for mysteries since.