So... edging on in my quest to control login/logout myself I've managed to figure out how to redirect to my own logout URL when clicking the Logout button by editing the umbraco.services.js (approx line 11335) from this:

logout: function logout() {
    return authResource.performLogout().then(function (data) {
        userAuthExpired();
        //done!
        return null;
    });
},

to this:

logout: function logout() {
    authResource.performLogout().then(function (data) {
        userAuthExpired();
    });
    location.href = '/logout';
},

What I would like to do is to add my own logout2() rather than edit logout(). So I've tried editing the logout button in user.html from:

<umb-button
    alias="logOut"
    type="button"
    action="logout()"
    shortcut="ctrl+shift+l"
    button-style="danger"
    label="Log out"
    label-key="general_logout">
</umb-button>

to

<umb-button
    alias="logOut"
    type="button"
    action="logout2()"
    shortcut="ctrl+shift+l"
    button-style="danger"
    label="Log out"
    label-key="general_logout">
</umb-button>

but login2() is never called.

Can anyone shed some light on what I'm missing?

Thanks in advance

Edit: I found out that if I edit routes.js, the doLogout function, I can direct that to logout2() and leave the button untouched...