Homepage slider not displaying on mobile (OK on desktop browser) – W3 cache?

Hello all, Hope someone can help me here. My site at https://davidyoungs.net has been up for ages using Catch Everest Free theme (thanks Catch Themes..) Recently I tried to improve the page load / speed of the site using W3 Total Cache plugin. It certainly made things a bit faster but I noticed immediately that the home page slider and its content had vanished on the site (on both mobile and desktop browsers). Same for the 'featured posts' on the front page, which have details about my CDs / strings etc. I deactivated and ultimately deleted W3TC, as soon as I deactivated it the desktop site returned 100% to normal with the slider posts and featured posts all correctly displayed. But when viewing on my mobile (Chrome Browser or native Samsung browser) the slider and featured post content is not displayed. The text which is below that content is all there a-OK. Tried updating to very latest version of the theme, but still the same. Anyone got any ideas of how to fix this please? Thanks in advance for any help! David