logitech harmony remotes should be able to run the remote codes for the m-f a308 - go to their site see software for their remotes, in it you can search the brand/model of gear and it will confirm if it can be loaded into the remote via usb
or else there is aftermarket replacements these guys will sell you... https://www.replacement-remote.com/products/musical-fidelity-a308-replacement-remote-control-4108?gclid=Cj0KCQjwgYSTBhDKARIsAB8Kuku6h-8SnrhneHvAF3PqLhtMaplJghreoDsbZoDQqY89nwRybDMjgBQaAjH_EALw_wcB