There is a plugin called redirection used for all the 301 redirects required. I have tried changing the URL monitoring to Don’t monitor as I read this on another post, but it still hasn’t helped.
If I change the permalink to ad a -xxx or anything at the end of -supplements, then the page loads, but if I try and use just the -supplements or -supplement then the page will not load.
Regarding the .htaccess file, I have not looked at this, but then don’t know what I should be looking for?