I bought a peugeot 306 last year and went on holiday for a fornight shortly after, when I returned the battery was dead and the car wouldn't start, I managed to get it working again by jump starting it, but it didn't last and the battery died (could charge or jump start it)

I replaced the battery and all was well again, until a fortnight ago, I went to start the car and just like before the battery was drained, again, I jump started and all was well again, for about a week and its now drained again.

I got a multimeter and did some tests on the battery the voltage is only showing as 11.7v, so I decided to check the current being drawn from the battery while the car was off and stereo is unplugged, it's showing as 20mA, when I plug the stereo in and do the same test it shows as 30mA.

Does anybody know or does anybody have a fully working 306 that can test to see if this is correct, I can't imagine a drain of 20-30mA being enough to drain the battery in a fortnight. My next test is to test that the alternator is working correctly and charging the battery. I recon the alternator is fine as the car was problem free for about 10 months after I changed the battery. I also noticed the other day, the light doesn't come on when you get in the car, it was flickering really quickly last week so I turned it off, now it doesn't come on when I open the door, but works if I switch it to the on position, aswell the light in the boot goes out if I put anything heavy in there.

Does anybody have any ideas on how to find this fault?