Had my 09 Octy 2 since summer 2021. Alarm unlock chirps never worked, never thought anything about it tbh. Started with low battery warning about 6-8 months ago. VAG specialist disagnosed as alarm siren dead and draining the battery as will trigger hazards when the vehicle is left locked. Have found hazards going regularly when parked up on the drive. Ongoing workaround has been to disconnect the battery.

Have installed a new aftermarket siren from Aliexpress but still suffering with the same issues. No unlock chirps and battery drain continues. ATA definitely switched on via dash options. Could this be a wiring issue relating to the alarm? 

Please help! Thanks in advance for any ideas or suggestions.

Not sure if its any help but had similar problem on old Volvo940. Replaced siren and had the same problem. Finally found out that theres a back up battery for the siren in case anyone decides to remove the battery terminals to stop the alarm. Not sure if Skoda is the same. It  was cooked and taking the charge from the battery. I only discovered it when it nearly went on fire and noticed an acrid smoke smell. It was in a box that was riveted to the chassis in the most unaccessible place. As the car was old and I reckon no one would steal it so I just removed it and had no alarm. As for the hazards operating when parked up My old octavia 08 used to randomly set off the alarm. Theres a sensor I think near the interior light cluster that gets dusty and triggers phantom alarms. I hoovered it out and since then no probs.

Alasdair