I would take it back to the dealer and tell them what the AA man said re-current draw. It could be that the battery is faulty and not holding charge. The dealer will have a tool that can test the battery.
As for the 300 mA that is excessive with all loads off and
's asleep. Some
's ie Injection can take 20-30 minutes to go into power saving mode. This is why somtimes you can hear the cooling fans running after the car has stopped and been locked.
The fact that the car wont start after 4 days shows that there is a fault. Even if it is just that the battery needs a good charge.