Hello Guys,
Thank you Darren for asking,

Ads are managed under adminc> advertising>

There are 3 ways to make them responsive.

1. Easiest way is to recreate your google ads in adsense and pick the responsive ads.
2. Fix the old code and apply the responsive one which you can do below changes.

For example normal ads:
Quote:
<ins class="adsbygoogle"
style="display:inline-block;width:728px;height:90px"
data-ad-client="ca-pub-2517459423514138"
data-ad-slot="2028335009"></ins>

make responsive by these changes.

Quote:
<ins class="adsbygoogle"
style="display:block;"
data-ad-client="ca-pub-2517459423514138"
data-ad-slot="2028335009"
data-ad-format="auto"
></ins>


no3. Aplying a css class to the current Google ads by following this example https://support.google.com/adsense/answer/6307124?hl=en.
That set of css class should not be in where the ads code are placed, you must put it in additional.css or inside</head> tag, this in vbulletin 4 is headinclude or headinclude_bottom template.