Permalink Issue

Hello,

Very new to WordPress and I am having trouble with the website (that I have inherited) as showing the website URL twice in the the permalink.

I have tried to flush the Permalink and that hasnt worked. As a test I set the Permalink to Default:”Plain” and the duplicate URLs disappeared so I think that Permalink is the issue but I am lost where else to look

Could it be a Theme issue? Or a Plugin etc?

Any help would be greatly appreciated

The page I need help with: [log in to see the link]