In the novel A Murder is Announced, Evans is a person living in Chipping Cleghorn and employed at Little Paddocks. Letitia Blacklock asked Evans to light the central heating for her on the day of the "murder party" at the house.
Evans's exact job at Little Paddocks is not given. However Letitia Blacklock does mention later that she has a jobbing gardener who comes in on Tuesdays and Fridays. As the "murder party" took place on a Friday, Evans is most likely the jobbing gardener.