Anyone got any idea how I can get rid of an unwanted search button/form?

My site is at :

http://www.a1-media.co.uk/catalog

I want to keep the search form which appears on the banner, but not the one that is just below it in the right banner section.

I dont seem to be able to remove one without the other.

I can see the code I'd like to remove when I view the page's source code.
However, Im not sure where I need to go to actually edit this.
(or whether I should actually be doing this)

Cheers...Jaz