RE: Warning: Parameter 1 to FeedWordPressHTTPAuthenticator::set_auth_options() expected to be a reference, value given in …
A quick update. I’ve rolled back to WordPress 4.61 and can now log in. Still have the error at the top of the page but at least I can access again. Have a back up of plugins using UpDraft Backup plugin and I’m in the process of restoring the plugins folder, pre update now.
As best I can determine, there’s a plugin incompatibility here.