Crime and Historical Novelist
All these books have a crime/thriller/mystery angle. Most of them are unobtrusively connected with the adult fiction (eg through minor characters or locations which appear in both).
The themes include illegal immigration, the dangers of nuclear power stations, experiments on animals, and conservation. Snapshot, Double Exposure and Negative Image form a trilogy. The others are one-offs. Private Nose is a tribute to the Sherlock Holmes stories, which features Saturday Holmes and her best friend Jack Watson. Hairline Cracks was widely hailed as a taut, fast-moving thriller. The Invader is a novel for older teenagers.
The earlier ones were originally issued under the name of John Robert Taylor.