What a truly fascinating story and history - thank-you.
I have read many books where that particular knife had been mentioned, specifically my studies of the SOE, and I have read about William Fairbairn and the Shanghai Municipal Police, may have been a semi-fictional account of his life and the development of a variant of another knife.
Fascinating, I hadn't heard Kali or Escrima mentioned in years, I've read a little about is the extent of my exposure to it.
You sound like someone worthy of a novel yourself...thanks again.