Hello @nickH-5, welcome to the Toolset support Forum!
This is the content of the other ticket: "Our developers concur that this is an Avada problem, and we are not going to try and fix their CSS which breaks Bootstrap. We are communicating that to them, you may want to point this out to Avada, too.
You can verify this on a site with Avada installed and no Toolset plugins.
Visit the page on the front end and confirm that the columns don't collapse.
It appears that they only break the sm column stacking, so you could change the default column width in your settings at Toolset > Settings > Layouts to another size such as xs."
Please let me know if it worked for you. Another option is to create a custom class then use CSS + Media Queries to hide the content on mobile.
Unfortunately, the way your answer is presented in the toolset ticket is unhelpful as it contains a hidden link (as does the original reply). See attached screenshot