The actual performances are mixed. Both Katy Manning as Miss Blacklock and Claire Fisher as Dora are extremely good, making their characters fully credible. John D Collins as Inspector Craddock] and Mark Martin as kicking-away-from-the-maternal-apron-strings Edmund are also good portraits. All are audible throughout, which (alas) is more than can be said for Geraldine Newman's Miss Marple – she looks right and has the mannerisms to a tee – or Dean Gaffney's Patrick.
Manning changes from the caring woman of the first scenes to a more visibly-hardened person with considerable subtlety. Fisher gives the slightly retarded Dora that voice which switches from normal to a near-shout which one associates with those who have been hard of hearing all their lives. And Collins produces the right air of exasperation when needed while giving the comic moments their full weight. You can't really produce much liking for Edmund, but Martin wisely doesn't try to make us.
Gemma Bissix as Julia
and Poppy Meadows as Phillipa don't really contrast sufficently.
They may be two of a type, but they're not peas in the proverbial
pod. The Blacklock household has a resident maid (this being "Agatha
Christie Time"); Mitzi is a refugee with a shaky past and an
inflammable temper. Julia Main makes her funny but also works hard to
turn a caricature into someone who might well have gone through the
personal and political traumas which she alleges.