Serious incident to the Airbus A320 registered 4R-ABM operated by Srilankan Airlines en route (Indonesia)

Preliminary data based on the notification from the Sri Lankan authorities:

Aircraft had dispatched with MEL 30 31 02a, FO pitot heater inoperative.
While flying, ECAM generated anti ice f/o plus stby pitot. Flight crew had carried out ECAM procedure and contacted mcc and had continued the flight. After ETOPS exit point ECAM ap, athr off aircraft went into alternate law with nav adr disagree unreliable speed. The flight crew had carried out unreliable speed procedure and ECAM procedures.
The flight crew had declared pan pan declared and requested block flight level 330 and 350. Jakarta control had cleared them fl 300 and 350. Overspeed warning generated, while maintaining fl 330 and 280kts on PFD1, stall warning generated. The flight crew had carried out stall recovery procedure and declared mayday and had requested direct radar vectors to WIMM airport. Aircraft landed at Medan a/p safely in direct law.