I have created a sidebar for a client as requested:
The top bar – where on other pages menu items are shown – is left empty as requested and instead 3 menu items are show in the sidebar. These lead to the three main sections of the site.
The client said the menu is not clear enough and I do agree. We only do not agree on location as I preferred the choices in the horizontal bar.
I decided to see how the sidebar menu can be made prettier. Client was inspired by http://smeekens.live.addsite.nl/praktijk so perhaps I should add a sidebar background for contrast?
How can I make the sidebar more prominent?
I have added menu items to the horizontal menu and I have added a background to the menu. It looks a lot better now. Thanks for all input!
Your best bet is to add a background color to the menu so it is distinguishable from the rest of the page. However, I would explain to your client that it is important to maintain structured navigation throughout their site, otherwise visitors will be confused by a sudden change. (That is, if some pages use the horizontal navigation and others use the vertical navigation.)