404 errors for top-level pages

I’m developing a site to use WordPress as a CMS, and I’m getting 404 errors trying to navigate to pages in the top-level of the page hierarchy. The problem lies with the custom theme I am developing I think.

Unfortunately I’m still developing my site on my own computer, so can’t give you a link to it, but I hope I can describe the problem in enough detail.

I have a number of top-level pages. One of them, called ‘Home’, I have set as my static home page and ‘Blog’ as my default posts page. I can navigate to home and to any sub-pages, but not the other top-level pages – I just get the 404 page. The links are being correctly created by wp_list_pages(), and the problem goes away if I switch to the default theme. I assume that means the problem is not the permalinks either.

e.g.

https://localhost/wordpress/ - works (shows 'Home' page)
  https://localhost/wordpress/home/staff/ - works
  https://localhost/wordpress/home/history/ - works

  https://localhost/wordpress/home - doesn't work (but you can get to it from https://localhost/wordpress/ anyway)
  https://localhost/wordpress/blog/ - doesn't work
  https://localhost/wordpress/facilities/ - doesn't work
  https://localhost/wordpress/facilities/accommodation - works

My question is: if the problem is with my theme, where should I be looking? The theme is still pretty basic and I haven’t tried anything too adventurous.

Thanks for your help!