Thank you Robin and Chris for your excellent advice and reference links.
I have found the solution – it was an error of manipulation on my behalf. Unwittingly I overwrote the index.php of the site with the index.php from the theme.
Had I not gone through the steps you outlined I still would be pulling my hair out – so a profound ‘Merci’ .
tourainedesign.
I have done all development on the web server so no migration needed.
wp-debug – do I activate this in the backend or via phpAdmin?
I shall do as you suggest regarding another theme and see if the problem persists.
No I have not – as this has been uninstalled.
