Hello, @Bas Kling,
I have checked your site there is no “#etheme-static-block-7” block on your site nor it is set at any place. All the static blocks on the site are coming from the Dashboard >> Static blocks there is no other place to find or create the blocks. If you need to create a new block or you want to edit an existing block you have to go to the Dashboard >> Static Blocks only.
Note: If you see the block “#etheme-static-block-7” on your site just show me a screenshot and share the page URL.
Regards 8Themes Team.