Can’t choose ‘Select Content Type’ in Solid Constuction theme

Hi, I am unable to choose the content type under the services section in theme settings. The option simply doesn't exist and frustratingly, it's preventing me changing the type to'Page' and limiting me to posts created under the Services section. How can I point a service to a page (one that also exists in my menus) so I can align and have more options with the art work? Thanks