Ok! I'm making progress thanks to your help. I cant get an error log from anywhere in the 1and1 control panel, but have been trying a process of elimination.
By selectively uploading files, I have now managed to get the home page to show up when I load all the files EXCLUDING the .htaccess file. Unfortunately, none of the links work to the 'sub' pages, I am getting a .404 error when I try and access each of these. If you want to see for yourselves, please feel free to look: http://www.english-works.co.uk/
So am I correct in thinking the error is in the .htaccess file?
This is the code in the file I have pasted in from notepad:
DirectoryIndex index.php index.html
AddType 'text/html; charset=ISO-8859-1' html
php_value include_path "./:../:.../"
php_flag register_globals on
#code to rewrite static to dynamic for detail pages
RewriteRule ^intensive-english-courses/([^/]+)\.html /detail.php?option=$1&detailType=T [L]
RewriteRule ^course-structure/([^/]+)\.html /detail.php?option=$1&detailType=TB [L]
RewriteRule ^learn-english/([^/]+)\.html /detail.php?option=$1&detailType=C [L]
RewriteRule ^thankyou.html /detail.php?option=thankyou&detailType=T [L]
Any thoughts/suggestions greatly appreciated!