Help with a custom nav walker

I am trying to create a custom walker that will output the following code / menu:

<ul>
	<li><a href="#" title="">Menu 1</a></li>
	<li><a href="#" title="">Menu 2</a></li>
	<li class="hasDropdown">
		<a href="#" title="">Menu 3 - Level 1</a>
		<div>
			<div>
				<h5>Description 1</h5>
				<ul>
					<li><a href="#" title="">Menu 3 - Level 2</a></li>
					<li><a href="#" title="">Menu 3 - Level 2</a></li>
					<li><a href="#" title="">Menu 3 - Level 2</a></li>
					<li><a href="#" title="">Menu 3 - Level 2</a></li>
					<li><a href="#" title="">Menu 3 - Level 2</a></li>
				</ul>
			</div>

			<div>
				<h5>Description 2</h5>
				<ul>
					<li><a href="#" title="">Menu 3 - Level 2</a></li>
					<li><a href="#" title="">Menu 3 - Level 2</a></li>
					<li><a href="#" title="">Menu 3 - Level 2</a></li>
					<li><a href="#" title="">Menu 3 - Level 2</a></li>
					<li><a href="#" title="">Menu 3 - Level 2</a></li>
				</ul>
			</div>

			<div>
				<h5>Description 3</h5>
				<ul>
					<li><a href="#" title="">Menu 3 - Level 2</a></li>
					<li><a href="#" title="">Menu 3 - Level 2</a></li>
					<li><a href="#" title="">Menu 3 - Level 2</a></li>
					<li><a href="#" title="">Menu 3 - Level 2</a></li>
					<li><a href="#" title="">Menu 3 - Level 2</a></li>
				</ul>
			</div>

			<div>
				<h5>Description 4</h5>
				<ul>
					<li><a href="#" title="">Menu 3 - Level 2</a></li>
					<li><a href="#" title="">Menu 3 - Level 2</a></li>
					<li><a href="#" title="">Menu 3 - Level 2</a></li>
					<li><a href="#" title="">Menu 3 - Level 2</a></li>
					<li><a href="#" title="">Menu 3 - Level 2</a></li>
				</ul>
			</div>
		</div>
	</li>
	<li class="hasDropdown">
		<a href="#" title="">Menu 4 - Level 1</a>
		<div>
			<div>
				<h5>Description 1</h5>
				<ul>
					<li><a href="#" title="">Menu 4 - Level 2</a></li>
					<li><a href="#" title="">Menu 4 - Level 2</a></li>
					<li><a href="#" title="">Menu 4 - Level 2</a></li>
					<li><a href="#" title="">Menu 4 - Level 2</a></li>
					<li><a href="#" title="">Menu 4 - Level 2</a></li>
				</ul>
			</div>

			<div>
				<h5>Description 2</h5>
				<ul>
					<li><a href="#" title="">Menu 4 - Level 2</a></li>
					<li><a href="#" title="">Menu 4 - Level 2</a></li>
					<li><a href="#" title="">Menu 4 - Level 2</a></li>
					<li><a href="#" title="">Menu 4 - Level 2</a></li>
					<li><a href="#" title="">Menu 4 - Level 2</a></li>
				</ul>
			</div>
		</div>
	</li>
	<li><a href="#" title="">Menu 5</a></li>
	<li><a href="#" title="">Menu 6</a></li>
</ul>

I would like the code to be clean with only a single class to define where a dropdown occurs. I have read numerous articles on the walker class and have tried creating my own from the nav-menu-template but cannot seem to understand it enough to achieve what I would like.

Please can anyone help? Many thanks in advance.