England at War — Rex Lee Applegate

We live in blissful ignorance of the turmoil wrought by timeline tampering. The new past creates a new present and we never know it. That is, if one is there to contemplate the story. Those whose existence has been erased are less than dead - they just never were. Harry and Karen are part of a small group acutely aware of this travesty. Their task is to restore history, as best as possible, when others have disrupted the timeline. It weighs on them when this role makes them purveyors of mass extinction...and creation. They believe what they do is for the greater good, but there is no escaping the fact that this work is a brutal, nasty business. Book Two of the Broken History series, which stands alone, deals with changes to outcomes in the Battle of Britain, the Napoleonic wars and the Spanish Armada. Putting things back was messy. The debris is there to see, if you look for it.