Hybris Marketing Content Studio editor adding additional html code to emails

Hi

After uploading email html code into the content studio email editor and doing a test send - i have noticed that the email received has additional html code / tags within it that are affecting the layout/design of my email template - particularly in Microsoft Outlook. Some examples of the code that is being added are below. The first is conditional styles for Microsoft Outlook clients, the second is an example of <div> tags added after reusable block content.

Any help / advice would be appreciated - i'm hoping there's a configuration setting to stop the editor adding it's own code?

Thanks
Jerome

<!--[if mso]>
    <table border=3D"0" cellpadding=3D"0" cellspacing=3D"0" align=3D"left" style=3D"mso-table-lspace:0pt;  mso-table-rspace:0pt; border-collapse: collapse; width: 100%">
        <tr>
            <td style=3D"width: 100%;">
<![endif]-->


<div style=3D"float: left; width: 100%" class=3D"sapMktBlock">