Gardam’s late-career flourishing began with a trilogy of novels about an expat British lawyer in Hong Kong. Now retired to rural southwest England, he appears in two of these stories, in which he finds that his new neighbor is a “jumped-up” former colleague. Gardam claims a terrain of social comedy somewhere between “The Diary of a Nobody” and P. G. Wodehouse. The former colonies loom large, like a phantom limb, while Britain itself feels very small. One story reflects how coded the mannerisms of this class are: two couples, meeting on vacation, are so alike that each doubts the other can be real. The effect is unnerving but not quite chilling. Gardam’s style is too cheery and content for that.