Actually quickly solved it myself. I’m a relative newbie, so just didn’t know where to start hence the panic when I was locked out. Looking through other support posts I learned the first thing to try was renaming the renaming the evil plugin folder serverside. On doing so I was immediately able to access my control panel and saw WordPress had actually recognised the plugin was bad and disabled it. Its a shame it couldn’t repair the damage also.
For the record it was Ready!Backup ver 0.2.1 upgrade. I’ve deleted it.
