Hi Seb,
Sorry for the late reply – there were some issues with the forum topics content we had. It’s ok now so we can get into this.
The Swipebox icons are inserted via inline styles, but you should be able to modify that via !important attribute.
I’d try to define all the background attributes, like background-image, background-size, background-position. If that does not work svg, try switching to png icons instead.
Hope this helps.