FYI also…
I did not need to enter my seed phrase in the setup of my 2nd RPBlitz install today. As I entered intitial setup, my initial install was recognised (I guess the relevant data was on the external SSD). I simply re-entered the requested passwords in the initial setup screen on the new install (the same ones I used on the first RPBlitz install) and the server started and showed my BTC balance, as well as the Electrum Rust server app which I installed after my initial setup on my first time around.
I add this in case it helps you or other readers. Again thanks for your help so far