Thank you for the speedy response aaPanel_Kern 🙂
I only get 404 Not found errors on specific interactions such as clicking on the link to go to the course or on the Go Back button 
as per the attached image. Yes I've added that entire block as is - i.e.:
charset utf-8;
location @rewrite{
rewrite ^/courses/([^/]+)/scorm/(.)$ /main/document/download_scorm.php?doc_url=/$2&cDir=$1 last;
rewrite ^/courses/([^/]+)/document/(.)$ /main/document/download.php?doc_url=/$2&cDir=$1 last;
rewrite ^/courses/([^/]+)/work/(.)$ /main/work/download.php?file=work/$2&cDir=$1 last;
rewrite ^/courses/([^/]+)/upload/(.)$ /app/courses/$1/upload/$2 last;
try_files $uri /index.php;
break;
}
location / {
rewrite ^/courses/([^/]+)/$ /main/course_home/course_home.php?cDir=$1 last;
rewrite ^/courses/([^/]+)/index.php$ /main/course_home/course_home.php?cDir=$1 last;
rewrite ^/badge/(\d+)/user/(\d+)$ /main/badge/issued.php?skill=$1&user=$2 last;
try_files $uri @rewrite;
}
location /main {
rewrite ^/main/admin/$ /main/admin/index.php last;
}
location ~ .php$ {
client_max_body_size 20M;
try_files $uri /index.php$is_args$args;
rewrite ^/certificates/$ /certificates/index.php?id=%1 last;
rewrite ^/courses/([^/]+)/$ /main/course_home/course_home.php?cDir=$1 last;
rewrite ^/courses/([^/]+)/index.php$ /main/course_home/course_home.php?cDir=$1 last;
rewrite ^/session/([^/]+)/about/?$ /main/session/about.php?session_id=$1 last;
fastcgi_pass unix:/tmp/php-cgi-74.sock;
fastcgi_split_path_info ^(.+\.php)(/.*)$;
include fastcgi_params;
fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
fastcgi_param HTTPS off;
}
location ~* .(png|jpe?g|gif|ico)$ {
expires 1y;
access_log off;
rewrite ^/courses/([^/]+)/course-pic85x85.png$ /app/courses/$1/course-pic85x85.png last;
rewrite ^/courses/([^/]+)/course-pic.png$ /app/courses/$1/course-pic.png last;
rewrite ^/courses/([^/]+)/scorm/(.)$ /main/document/download_scorm.php?doc_url=/$2&cDir=$1 last;
rewrite ^/courses/([^/]+)/document/(.)$ /main/document/download.php?doc_url=/$2&cDir=$1 last;
rewrite ^/courses/([^/]+)/work/(.)$ /main/work/download.php?file=work/$2&cDir=$1 last;
rewrite ^/courses/([^/]+)/upload/(.)$ /app/courses/$1/upload/$2 last;
try_files $uri @rewrite;
}
location ~ .(ht|git){
deny all;
}
location ^~ /tests/ {
deny all;
}
