Thanks for all your help with this. Learning HTML5 has not been as simple as I first thought it would be. It is apparent that there are very specific combinations of style that need to be inserted, sometimes in the right order, and if you get just one of those wrong then the whole of what you are trying to achieve won't work.
Great challenge though.
With the help from the forum I have been able to achieve exactly the layout I was looking for.
Here's my fiddle for anyone else interested in this layout. http://jsfiddle.net/Ruddlesdin/rrHru/4/
(And I name this layout "Paul's Layout" unless there is already a name for this layout)
<body id="body"> <div id="wrapper"> <div id="header"> <div id="headerLeft">1</div> <div id="headerRight">3</div> <div id="headerMiddle">2</div> </div> <div id="main">4</div> </div> <div id="footer">5</div></body>
body,html{ height:100%; margin:0; padding:0;}#wrapper { height:100%; position:relative; width:100%; margin:0; padding:0;}#header { height: 50px; width: auto; background: orange;}#headerLeft { float: left; width: 100px; height: 100%; background: green;}#headerMiddle { height: 100%; background: red;}#headerRight { float:right; width: 100px; height: 100%; background: blue;}#main{ background:yellow; width: auto; height:80%; /* Not sure where the figure 80% is calculated from but it worked for me ???? */}#footer {position:fixed;bottom:0px;height: 50px;width: 100%;background: pink;}