Remove header image using wordpress content slide

Hi,
I.m using the content slide plugin. I like to have a slider instead of a header image on the contact page only.

https://www.ads-software.com/extend/plugins/content-slide/
https://www.hollandvorm.nl/wordpress/contact/

I’ve put the php code for displaying only on contact page in the header.php however I’m now seeing both the content slider and the header image sitting underneath.

How do I make the other header image disappear off the contact page only? I’m using a the twenty eleven theme

Code here:

https://pastebin.com/0ygsxdKR

Thanks very much for help
Eric