Andy Smillie has 2 books in the Warhammer 40,000 catalogue, listed below in publication order with where each fits on the timeline.
Original summaries and chronology labels generated from the same catalog powering the atlas.
Andy Smillie
An anthology gathering novellas and short fiction about the Flesh Tearers, the savage Blood Angels successors who battle both their xenos and traitor foes and the murderous curse in their own blood. Following Chapter Master Gabriel Seth and his warriors, it spans the Chapter's violent origins and its desperate fights for survival in the 41st Millennium.
667.M41 - 999.M41
era date, medium confidence
Andy Smillie
Ultramarines and Word Bearers muster together at Calth in the fragile hope of healing the rancour left by the burning of Monarchia. As the two proud Legions gather, a captain's obsession and the lurking threat of treachery turn a moment of reconciliation toward catastrophe, told through interwoven past and present.
000.M31 - 333.M31
era date, medium confidence