All 3 topics mentioned above are connected with Independent Grenadier Company (SKG) - small company-size elite para-commando unit initially trained for special operations in France (Operation Bardsea). During the war unit was extended to Poles who earlier served in German Army (for projects Dunstable/SAARF).
Another story is OSS led "School of Specialists" - commanded and mostly trained by ex-SKG officers and soldiers.
The new book written by US author related to this formation was recently published in Poland:
A few years ago first book about Project Eagle based on Polish archives in London was published:
And also my article about School of Specialist in this book: