What great work you are doing!
I have personally purchased both a second hand refurbished CARDIAC SCIENCE POWERHEART AED G3 that had a new battery and pads installed and one of the small CellAED which is the lightweight version for approx $400.
https://cellaed.io/au is where you can get the lightweight one use version.
I originally purchased this after a family member had a very close call with a total heart block (not cardiac arrest) but prompted me to look into this as at 46 i am only getting older, and we were doing a remote trip to NT with a bunch of blokes over 45, it though it was good insurance and thank fully nothing happened and wasn't needed. I have since had 2x stress tests and a CT Angiogram personally and thank fully given a clean bill of health.
I have the AED G3 which stays at my home or comes in the car with us when going away, and i have also lent my CellAED to a friend who is travelling around australia.
i think its a must in your travelling kit, especially as we got older, so its well worth looking into, and its good to see so many pop up in community spaces as well.