Troubles with alarm and deadlock
 

On my V70R I have troubles with alarm.

When I open the car with remote and just sit inside without starting the engine, the alarm goes off after about half a minute. I can prevent this from happening with pushing the unlock button on the door from inside.

Same problem when stepping out of the car and leaving the car empty, but not locked with remote - after opening any door, the alarm goes off. I can prevent that again by pushing the unlock (either on remote or via opened window on door).

As well opening the drivers door from inside in case I am locked in the car (I lock myself when driving) is very difficult - I have to push the unlock button on the door first and then open the door.

And the lock in drivers door does not work with key (funny story when I took the battery from the car out to charge it, locked the car with opened bonnet with remote, then took the battery out and shut the bonnet - day after realizing, that the key in the keyhole in drivers door is just spinning and not unlocking :D )

Diagnostics gave me trouble code VGLA-312 Siren internal battery fault.

Any ideas? I suspect that I am having two problems at one place - with siren and the drivers door lock.