Hi,

I think you was over complicating what you wanted to achieve

I have created a simple fluid layout for you.

https://litmus.com/builder/98fe2fc

Using min and max widths to find the screen size and MSO conditioning statements to set the boundaries for outlook.

It was a quick creation but pretty confident it will be fine in all ISP's

There a post on MailChimp explaining all about fluid email layouts

Thanks

Will Varley - I got this email

Just a very funny song about emails :)

You needed to nest the whole email with a table.

See what i've done here

If you put align="center" on the parent TD of your master table then that should work.

If your having problems then post your code and i could take a look for you

Thanks

https://litmus.com/builder/d3306bb

I don't have an explanation why what I've done has fixed it but just that it worked

<table width="640" align="center" border="0" cellspacing="0" cellpadding="0" >
                <tr>
                    <td background="http://homexblogs.wpengine.netdna-cdn.com/heassets12/files/DP001-LN-004-01.jpg" bgcolor="#1e8dae" valign="middle" style="background:url(http://homexblogs.wpengine.netdna-cdn.com/heassets12/files/DP001-LN-004-01.jpg) no-repeat center;text-align: center; background-position: center center; background-size:cover;">
<!--[if mso]>
<v:rect xmlns:v="urn:schemas-microsoft-com:vml" fill="true" stroke="false" style="width:660px;height:270px;">
<v:fill type="tile" src="http://homexblogs.wpengine.netdna-cdn.com/heassets12/files/DP001-LN-004-01.jpg" color="#1e8dae " />
<v:textbox inset="0,0,0,0">
<![endif]-->
<div>
<!--[if mso]>
<table align="center" border="0" cellspacing="0" cellpadding="0" width="500">
<tr>
<td align="center" valign="top" width="450">
<![endif]-->
<table align="center" border="0" cellpadding="0" cellspacing="0" width="100%" style="max-width:500px;">
<tr>
<td valign="middle" style="color: #ffffff; text-align: center; padding: 50px 30px; font-family: 'Roboto', sans-serif; font-size: 18px; mso-line-height-rule:exactly; line-height:1.2;">
Travelling without spending a fortune isn't always easy. And sometimes you just don’t want to sleep on the sofa or stay in Aunt Barbara’s guest room (no disrespect to Aunt Barbara).
<br><br>
Use these clever ideas from the HomeExchange Team to make the most of your travel budget without feeling like you’re cutting corners.
</td>
</tr>
</table>
  </div>
  <!--[if gte mso 9]>
    </v:textbox>
  </v:rect>
  <![endif]-->
</td>
</tr>
</table>

Hopefully this will work for you.

The main this is that i changed the outlook conditional statement to target all of outlooks versions rather than just one rendering engine

Hope this helps