I'm assuming you want to replace the search bar in the header: https://i.imgur.com/ipbo6Vd.jpg
I have tried to log-in to the site, but I'm getting this security notice: https://i.imgur.com/Sg1ZDpm.png
Can you also add temporary FTP details as well? I will try to find which file has that form integrated and replace it for you if possible.
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