I phoned earlier this morning and was told that you currently can not change your dial-up password - only your client-zone password. They are however looking at changing this.
At the moment you cannot unfortunately change your ADSL login password.
I'd suggest that you change your Client Zone password to something that you'll remember. Then if you do ever need your ADSL password you can login to your Client Zone and get it from there.
I have asked our developers to look into adding the functionality to enable you to change your ADSL password too.
Is is also possible to have a activity monitoring function on the site? It would be nice to see if the account is activated/authenticated for more than one session.