We had a similar issue at my last employer when hand-held extinguishers and life jackets were downgraded from rotables to consumables. It meant that we had no idea what was where, and we were only a cargo airline!
In the end we did as suggested by Mr @ Spotty M, and had regular checks, even daily in some cases, to confirm that essential safety equipment was installed and in life. A bit time-consuming but when you are dealing with "No go" items, probably the only way.
I once worked for a outfit headed up by a bent Middle Eastern A & P who on one occasion sold his company 727's cabin fire extinguisher to another operator, and then sold another fresh one back to the first aircraft
