This PvZ replay has the folllowing:
- Proxy in the exact location you describe, behind 2 gateways.
- Successful scout with a Drone, no gateways or cores so immediately looks for the proxy.
He does this in both Tzenes spot (in vision of his drone) and your spot. - Successful scout with an Overlord, nothing in Tzenes spot nor gateways after the Drone leaves.
- The Zealots, Stalkers and Proxy being countered by Zerglings and Roaches.
- This is followed by an expand by Zerg and a series of pushes by both players.
Although Zerg didn't win in the end, I consider he countered the Proxy fine and messed up later.
If you want, just ask and we can try to figure out what went wrong later...
See the end of this answerSee the end of this answer on how Terran (MM) and Protoss (2gate) counter with the same scouting.