In the last two weeks I started to get the 4 blips from the Alarm Siren on switching the ignition.

Today I took the Siren out and rather than replace as Audi would have you do, I followed the steps here

Seems to have done the trick, I used a junior hacksaw to saw the Siren in two and soldered on some new batteries as per the instructions.

Parts cost around 15, which is surely better than giving 80 to Audi.