Stewart sent me a trace of that case saver plate a few years back and I made one up from a slab of steel plate (thanks Stewart).
It took about an hour all up - Vice, hacksaw, drill and angle grinder. Plus the side out of a Weetbix box as a master template which can be used as the basis for recreating different sized guards for different front sprocket sizes.
You need to have the steel plate just clearing a properly adjusted chain so the chain cannot jump off the front sprocket, really simple but effective.
Nice PE collection there Prospector, welcome aboard.