You can get a copy of Zip as part of this campaign's indie comic book bundle expansion pack! It's a stretch goal, so pledge to get the campaign to its target and unlock the bundle.

The amount of places in Bristol which can literally be described as "a maze of secret underground tunnels, lost to time, so vast that they haven't been fully explored" is so numerous that there's enough material there for like, two volumes worth of Zip stories all by themselves.