Hi all, I have a 2003 TD5 110 Defender which has sat on the drive for several weeks and the battery has gone completely flat. I have tried to charge the battery but as soobn as I switch the booster charger on the alarm goes off. some years ago someone told me how to switch the alarm off with a combination o 'key position' and pressing the key fob so manny times but I can't remember. Can anybody help?

Loosen the earth lead on battery but leave it connected, switch ignition on then off and immediately disconnect the earth lead from battery, then remove the positive lead if you want to remove battery to charge or change battery. That is the way it says in my manual.
If there is enough charge theft in the battery lock the car and arm alarm with the fob then unlock it before doing the above.