Missing Access for Editing "Member Login" Screen in Mailman module

On the "HTML Page Editing" screen there is no link to the "Member Login Page" so it cannot be customised to match other screens a user sees.

On the bottom of "General list information page" there is a field and button marked "Unsubscribe or edit options" If a user clicks that button without entering a valid email address, they get sent to an uncustomisable default Member Login screen.

My request is for the missing link to be added to the "HTML Page Editing" page.

(Incidentally, while entering a valid email address sends you correctly to the "options" page, entering an address not known to the system sends to you an Error 500 screen. That doesn't seem right, but I'm happy to live with that!)