Hello to anyone reading this thread.
I sent details of my account to Aderson who very kindly checked access to certain pages on my site.
He found that he could access those pages, so refered back to me to check browser caching.
I've cleared my browser's cache (not cookies) and now have access to the page.
I did clear the cache many times before though and even accessed the pages using Chrome's incognito mode, so don't understand why it's working now but at least it's working :-)