Overlay logo onto featured image

Using the navigator theme, how do I overlay my logo onto the featured image?

The link I have provided is actually the landing page created using the WP Maintenance plugin but it's useful because it actually shows what I'm trying to achieve in the Navigator theme.

I followed David's steps in another thread, where he recommended creating a new GP header (in this case I created a new element) but it didn't work.

Just to summarise, I would like Navigator's header/page hero to look like the link I have provided.

Also is there any way to stop the page hero pushing down the content of my posts?

Thanks in advance