Drop some mothballs down the holes, I've heard that works. I think the hardware cloth should last longer than that, it's galvanized. Maybe they climbed up the sides?? I don't picture gophers as climbers, but as I recall, your beds have 2x6 or 2x8 sides and a 4 inch long critter with claws might be able to climb a little. Did they eat the plant roots or just uproot them? You might want to call the extension office and ask, or google might tell you. I fight them in my vegie garden, and have trapped a few.
