How can I adjust the gap between the Nav bar and the header?

Hello all,

My store link is https://shop-cnlselectronics.co.uk/ and password is hello, if its required.

I have reduced the height of my header to cut down on some unnecessary black at the top of the page. however, you’ll see I now have a gap between the Nav bar and the header. How can i reduce this so they meet please?

Many thanks,

Steven