Land Rover Repair: 2001 Disco II Rough Start, alarm button, battery terminals

Question
Hello, I have a 2001 Disco II with 79000 miles on it.  Just recently it began doing this thing that unlocking the door with the remote would unlock the doors but the alarm stays armed and goes off when you try to start it.  Also, when you try to start it it has trouble starting (it starts slow).  It is trying to turn over, not just making a clicking noise.  Pressing the alarm button on the key again gets the alarm to go off but it still turns over very slow, but will start.  I have reset the alarm by pressing the lock button 4 times rapidly but it is still turning over slow.  There is a bit of corrosion on the red terminal of the battery and some corrosion on the battery stay.  I think I need a new battery but the battery light isn't on.  What do you think?

Answer
If you have corrosion on the battery terminals you should certainly clean them up.  If the battery voltage drops below 10 volts when cranking, with a charged battery, you should  also change the battery.

That said, you may also have some issue with the alarm and that will require a dealer or specialist who can talk to the alarm computer.