BBC's Miss Marple
In the BBC 1987 adaptation of the novel, Giles Reed is portrayed by John Moulder-Brown. The portrayal is very similar to the original novel except that he is present from the very beginning. He and Gwenda go house hunting and undertake the subsequent investigations together right through. In this adaptation, he is the cousin of Raymond West and not Joan. He goes off to London to visit Raymond while Gwenda remains behind to supervise the renovations but she later decides to join him.
ITV's Agatha Christie's Marple
In the ITV 2006 adaptation of the novel, the character of Giles Reed is morphed completely into a different character with a different backstory. Here his name is "Charles Vanstone" and he is Gwenda's fiance and not her husband. He is a wealthy businessman, possibly head of Vanstone International. He remains behind in India because of business commitments and sends Gwenda ahead to buy a house and make wedding preparations in England and assigns Hugh Hornbeam, an employee of his company, to look after her. In contrast to the portrayal in the novel, Charles is unsupportive and unsympathetic to Gwenda's problems. He refuses to come to England even when she says she is afraid and needs him, citing his work. He doesn't play much of a role in the plot except to use his influence to get some background information on Claire Halliday from the Delhi police. Charles is much older than Gwenda. She describes him as "so worldly" and she tries to be worldly for him although it is not she nature. At one point she confesses to being afraid of him. At the end of the episode, she breaks off her engagement with him and agrees to marry Hugh Hornbeam instead.
Charles Vanstone is typically seen in shadow or from the back and the actor who portrayed him is not credited.
NHK's Anime adaptation
In NHK's anime adaptation of Sleeping Murder, Giles Reed does not show up until right at the end when the mystery has been solved. He does not play a role in the case at all. Presumably this was to allow Mabel West a larger role in accompanying Gwenda throughout most of the inquiries. The voice actor behind Giles' character is not credited.