URL Mapping doesnt work

I dont have the advanced membership to access HTML/CSS but I am trying link my photo in the article to an external page. I've followed the URL mapping instructions i.e. 

/articles/demolition -> http://igor.gold.ac.uk/~amclo002/Council_Blocks/TowerBlocks.html 301

but it still doesnt redirect me ti the correct page... only when clicked on title where I had altered Source URL 

OR is there an option to disable the URL for post in for the Basic Subscription?

Unfortunately the URL mapping won't work if the page is still live on your website.

You can disable the links on the thumbnails but the solution will largely depend on which template you are using. The below solution will work with the Brine family of templates if you place this in your sites global CSS.

You will still be able to add CSS on the personal plan.

.BlogList-item-image-link {
     pointer-events:none;
 }

If this doesn't work then let me know which template you are using.