Weird Battery Drain

[Gatesy]

I\'m having some really weird problems with my FD at the moment.  I\'ve got a brand new alternator fitted and a brand new battery fitted yet most mornings I come out of the house and its as flat as a pancake.  I\'m using the rex as a daily drive at the moment while I look for a little runabout but I\'m getting increasingly annoyed with the fact my battery keeps going dead.  I tried leaving the car with the alarm switched off last night and it was as flat as a pancake this morning (luckily I have a jump pack I keep in the boot now).  It seems no matter if I leave the alarm on or off the batts getting drained.  
I checked the alternator with a tester and it came up trumps but the battery came up with 2 out of 3 lights.  
Anyone got any ideas?