I've just visited all 4 Torval Megaships, to see if any of them work currently
LTT 198 (Permit Locked) / Zetian's Recall - Has a Tech Broker - Tech Broker menu will not load (Odyssey) / "Retrieving Blueprints" (Horizons)
EGM 559 / Pride of Bitterwood - No Tech Broker
21 Eridani / The House Ascendant - Has a Tech Broker - Tech Broker menu will not load (Odyssey)
Laguz / Champion of Commerce - Has a Tech Broker - Tech Broker menu will not load (Odyssey)
Edit: The Mining Lasers are available from the Tech Broker at the Megaships in: LTT 198 / 21 Eridani / Laguz