Thank you Brady for a quick reply. I went back and uninstalled all plugins and reinstalled simple page sidebars and yes, it works! There still appears a blank line in Appearance menu which links to an Edit Sidebars page that claims no sidebars to edit (I haven’t done any changes to the admin menu appearance), but I can see the extra sidebar on the Widgets page, so I can edit it fine. What a relief. I can’t tell you how frustrated I’ve been with my WordPress customising, getting blank pages every time I have to add something in Functions.php, and this plugin saves me from all that; thanks!
