Unfortunately, the user did not provide any information about the save-file. Maybe he will do this later!
Fallout 4: London
SaveGame Description
Installation
1. Download archive (Last Update: 6.11.24).
2. Extract files using 7-Zip (WinRar) ulillity program.
3. Backup your saves.
4. Copy the data to the following folder:
C:\Users\Your_Name\Documents\My Games\Fallout4\Saves. *
5. Run Fallout 4: London!C:\Users\Your_Name\Documents\My Games\Fallout4\Saves. *
* The paths may change depending on the version of the Operating system.
Download Save
Save Editor
Bad News! There is no save-editor (or information about it) found for this game! Sorry!