This is NOT an idea for a book. However, I know that your books are thoroughly well researched and so you may have stumbled across an interesting, ancient and venerable institution The Honourable Artillery Company in London (UK). It has a diverse (and crazy) 500 year history together with a usefully ‘undocumented’ further 500 year ‘pre-history’ (pre Charter of 1537). If I were a writer (and I am not) I would rummage around it ( or even come and visit the institution which is still there in Moorgate) and come up with an idea for a story. There. Not a story line! I’m not a lawyer either (although tragically my daughter is).
Keep churning out the good stuff!
All good wishes
MJH