Slick slide image aspect ratio help

I have a slick slider in my WordPress site, using bg images on the slick-slide.

I need to keep them at a set aspect ratio, which I know how to do and normally works great, but it's proving to be tricky on the slick slider.

When I add my usual aspect ration 'padding-top' to the slide, It just makes the slide/image really long: you can see this here: https://codepen.io/pixelboutiqueuk-the-lessful/pen/zYrZJgQ?editors=0110

When I add the padding-top to the slider itself, this looks like the right size, but then the slide image is pushed out of view (to the bottom).

Can anyone help?

Thanks