Mobile menu not working on iPhone

The mobile menu for spacious theme is not working on the iPhone. It works fine on desktop browsers and in web console when I shrink the screen down to test.
What happens is that the menu is there but I can’t tap it. It doesn’t select, so can’t be opened or used.
I tried updating to the latest version of the spacious theme and wordpress to no avail.
I have a child theme, but I even tried removing all references to the menu from the child CSS, so I don’t think that’s the problem.

The website can be found at https://allegroit.com.au.

Please help! I’ve searched for a solution but no one else seems to have this problem.