I've just been checking one of the emails that bypassed the filters and this is the HTML that was in the email:
<!-- Text with Title-->
<table class="at-MainTitle" cellpadding="0" cellspacing="0" border="0" align="center" width="83.3%" style="border-collapse: collapse; border-spacing: 0; margin: 0 auto; max-width: 83.3% !important; min-width: 83.3% !important; width: 83.3% !important;">
<tr>
<td align="center" valign="top">
<div style="line-height: 36px"><strong class="at-blockHeader at-TitleHeader" style="font-family:Arial, sans-serif;font-size:34px;line-height:36px;color:#333333;text-transform:uppercase;"> Your McAfee Antivirus Has Expired! </strong></div>
<div style="line-height: 36px"><strong class="at-TitlePostheader" style="font-family: Arial, sans-serif; font-size: 32px; line-height: 36px; color: #333333; text-transform: uppercase;"></strong></div>
</td>
</tr>
</table>
<!-- End Text with Title-->
As you can see the html has no gaps in the word 'McAfee'. Hopefully on Monday when the scammers start up again the filters will be tested again.