Thank you RodG. The answer was of course...user error

The template guy kindly sorted out my .htaccess file that I had tinkered with while considering the options for moving the shop from /shop/ to public_html

Also he apologised for not sending me the admin url for the seo urls management. It is different to the regular admin pages, so now I have control over the seo urls .

The site is now working again. Thanks for all the replies.