I’d be more than happy to work together on this, and I’d be really glad of some Beta testing.
I’ve found the OS API key database to be rather sluggish. If I make any change then after a while it gives referer errors, then some (or many) hours later it syncs up and starts working again. I’m still unclear whether the API key needs separate entries for http and https access, but it would be good to clear that up and add some FAQ entries to the plugin page to explain.