I have followed all the leads and got nowhere. Mac OS 10.10.3 running Safari.
I have a separate system on my computer - an admin one left behind after a repair was carried out - and have been able to load Flash Player in that but haven't worked out how to transfer the appropriate files to my normal system. What are the appropriate files and where do I put them? I have located Flash Player.plugin and transferred it to Internet Plugins. The other item I found was a folder Flash Player containing a folder AddIns contain airappinstaller but I don't think this is useful. I also found Adobe Flash Player Installer but this just offers to uninstall Flash Player. I couldn't find Flash Player as an application.