Lesley's early work was influenced by the lights of the Grangemouth petrochemical complex, leading her to paint predominantly cityscapes at night. More recently she has also begun to explore lights in other ways, focusing on interiors and the various lights they can convey.

Her commitment to exploring the nuances of light and shadow has also led her to experiment with new techniques and materials. She frequently uses materials such as resin, enamel paints, iridescent oil paints, gold leaf, and other mixed media to add luminosity and complexity to her compositions. This innovative approach not only distinguishes her work but also allows her to push the boundaries of traditional painting.