As an admin, it was nice to quickly "enable" or "disable" kits with them moving out of the menu from players' view with the remove. But not deleted for later use/ tweaks.

For Players/admins with permissions; Place an "add"  button Left of the "Create New" button, Top right of the main GUI

Add a remove button above Redeem of each kit on the main GUI.
Alternatively a simple enable/disable button in this location. 

Another option would be to create a manage kits interface/page and corresponding buttons; then the requested button at the top of the main GUI could be labeled "add/remove" or "Manage"