Mountain theme menus in mobile devices (AGAIN)

This is a common issue, I know. I’ve applied various fixes I’ve found in these forums to make the background non-transparent, and to move the menu above the hero banner so it displays - more or less - in mobile devices (Mountain Theme Menu Not Working).

Results are at https://bentshedproduce.com.au (still having an argument with the .htaccess to force it to use SSL).

Clearly, I’ll have to try and re-create the good bits of this theme (it’s that right-hand sidebar with the moving logo that’s the winner, I think) from scratch, once I learn how to do that.

In the meantime, however, I need this to work. I have several options in one of my menus. I can’t get around that BUT I have placed internal navigation in that section in the sidebar … can I somehow suppress the full drop-down menu for mobile devices, maybe? (Noting it seems to be fine in tablets, just phones)?

Has anyone any suggestions to make the menu less … ugly?

(Other than moving to another theme … if I wanted another theme, I’d use it … ).