After do-release-upgrade to 13.04 from 12.10 I still get informed about 13.04 on log-in via MOTD

This was an issue with moving to 12.10 it appears to have resurfaced now with 13.04 i.e. post upgrade to 13.04 you still get the MOTD to upgrade.

I've tried the previous list of fixes for the same issue re move to 12.10 https://askubuntu.com/questions/253844/upgrade-12-04-2-lts-to-12-10-do-release-upgrade-fails-no-new-release-found but they don't seem to work, i.e. there is no /var/lib/update-notifier/release-upgrade-available to remove.