Miss Marple: They Do It with Mirrors

I bought the whole series on DVD. But this closing instalment left me unimpressed. There are so many characters, some of them American, even Miss Marple struggles to keep track of who's who, who's whose ex-husband's son etc. None of them are particularly likeable or attractive, or interesting enough to make you care about them. A lot of speechifying goes on about "the youth are our future", nature vs. nurture, battling bureaucy... Yawn; and hardly the stuff Agatha Christie mysteries are made of. The direction looks inexperienced. The actors are either trying to get it over with or too keen to steal the show. Worst of all, Miss Marple becomes just an extra in this mess.