Custom Links not working

I am working on a new site on http://www.cordiners.co using the Elegant Themes Divi Theme, and whenever I set up a custom link instead of going to that section it automatically hides the row or section I am trying to jump to!
http://cordiners.co/timber-centre/timber-centre-products/#doors
should take to a section on doors & windows which you can see if you go to
http://cordiners.co/timber-centre/timber-centre-products/
but as soon as you use the ‘css id’ to jump to a particular part of the page, it just seems to hide the part you are trying to get to!
I’m so confused as to why! Have tried removing all plugins etc and no difference.