Duplicated Menu

I am using WordPress 4.4.2 with Theme Twenty sixteen version 1.1 and Mega Max Menu version 2.1.3 on website https://www.audley.one-name.net

Please note I am a family history researcher and not a website designer.
Somehow on my website I have managed to duplicate the menu on the right hand side at the very bottom of the web page. Whatever I try I cannot get rid of the menu at the bottom of the web page.

Can someone please advise in simple terms how to remove the menu at the bottom of the webpage.

If you do look at my website please be aware that at the moment most of the menu items are links to my other website

Thanks in anticipation of your help but please note my expertise in website design is very limited.

https://www.ads-software.com/plugins/megamenu/