Submenu Dropdown CSS Issue WordPress Flozo Theme

Hi,

I have an issue with my site, where I can’t get the Submenu’s to display properly. I have a main menu, and on the LED lighting entry there is a Submenu, which should have two items, however on hover, one of the items disappears. The Submenu is also not displaying correctly underneath one another, but side by side, even though I have list-item specified in the CSS.

The website is: https://www.pluginsolar.co.uk

The CSS for the main menu and submenu can be seen below.

ul#menu-main {
    display: block;
    margin: 8px 0px 0px;
    clear: both;
    padding: 0px 0px 0px 4px;
    background: none repeat scroll 0% 0% #EE4952;
    list-style: outside none none;
    height: 60px;
    font-family: BebasNeueRegular,Helvetica,Arial,sans-serif;
    font-size: 16px;
}
	ul#menu-main li.current-menu-item a{
		color: #333333;
	}

	 ul#menu-main li{
		float: left;
		line-height: 60px;
		z-index: 40;
	}
		 ul#menu-main li a{
    padding-bottom: 21px;
    padding-top: 20px;
    padding-left: 20px;
    padding-right: 20px;
			color: #fff;
			text-decoration: none;
		}
			ul#menu-main li a:hover{
				color: #333333;
			}
			ul#menu-main li a:hover.sub-menu li,
			ul#menu-main li a:hover ~.sub-menu li{
  			clear: both;
			display: list-item;
			}

ul.sub-menu {
/* text-align: left; */
clear:both;
display: list-item;
margin: 0;
padding: 0px;
list-style: none;
-webkit-box-shadow: 0 0 5px rgba(0, 0, 0, 0.15);
-moz-box-shadow: 0 0 5px rgba(0, 0, 0, 0.15);
box-shadow: 0 0 5px rgba(0, 0, 0, 0.15);
}
ul.sub-menu li {
/* font: bold 13px/18px sans-serif; */
/* border-bottom: solid 1px #FFF; */
/* border-top: solid 1px #FFF; */
clear: both;
margin-right: -4px;
position: absolute;
padding: 0px;
background: none repeat scroll 0% 0% #f6871f;
cursor: pointer;
transition: all 0.2s ease 0s;
display: none;
}
ul.sub-menu li:hover {
  clear: both;
  background: #000;
  display:list-item;
  color: #fff;
  margin-right: -4px;
position: absolute;
padding: 0px;
background: none repeat scroll 0% 0% #f6871f;
cursor: pointer;
transition: all 0.2s ease 0s;
float:left;
}
ul.sub-menu li ul {
  clear: both;
  padding: 0;
  position: absolute;
  border: none;
  top: 48px;
  left: 0;
  width: 150px;
  -webkit-box-shadow: none;
  -moz-box-shadow: none;
  box-shadow: none;
  display:list-item;
  opacity: 0;
  -webkit-transiton: opacity 0.2s;
  -moz-transition: opacity 0.2s;
  -ms-transition: opacity 0.2s;
  -o-transition: opacity 0.2s;
  -transition: opacity 0.2s;
}
ul.sub-menu li ul li {
  clear: both;
  background: #555;
  display: block;
  border: none;
  color: #fff;
  text-shadow: 0 -1px 0 #000;
}
ul.sub-menu li ul li:hover {
clear: both;
background: #666;
  display:list-item;
  color: #fff;
  margin-right: -4px;
position: absolute;
padding: 0px;
background: none repeat scroll 0% 0% #f6871f;
cursor: pointer;
transition: all 0.2s ease 0s;
}
ul.sub-menu li:hover ul {
  clear: both;
  display: list-item;
  opacity: 1;
  visibility: visible;
}

Any help with this issue would be much appreciated. Thank You.