LayerSlider: old jQuery issue

I am new to both wordpress and to this forum. Apologies if I have strayed from the path of “wordpress forum righteousness”.

I have googled the problem and all I get is lots of other sites displaying the same problem. I can see similar problems discussed elsewhere, but these do not resolve my problem.

The problems is that My Avada Theme layer sliders do not display properly since I updated to version 3.9.1. I have hidden most of the sliders, but you can see the problem here….

https://www.synergy-environmental.co.uk/contaminated-land-consultancy/

I get the following message “It looks like you are using an old version (1.11.0) of the jQuery library. LayerSlider requires at least version 1.7.0 or newer. If you are using the WordPress version of LayerSlider, you can try out the “jQuery Updater” plugin from the WP plugin depository. If you don’t know what to do, you can write us a private message from our CodeCanyon profile page. We need a temporary WP admin account (or a temporary FTP account in some cases) to solve this issue.”

I have jQuery updater version 2.1.1 installed but it doesnt seem to make any difference. I have noticed that the page options section used to allow me to select the avada theme for my layer slider type, but this option has disappeared.

Any help would be greatly appreciated.