Citroen Xantia Alarm

Can anyone tell me where you find the scuttle panel on a Citroen Xantia and what it looks like please? My key has stopped working and won't disarm the alarm so it keeps going off when I open & close the doors and the switch on the front panel isn't deactivating it either. I've tried disconnecting the battery but I assume it has a back up battery as it is still going off. Can someone help me please or give me a step by step guide on how to totally turn off the alarm system. Its a P reg Xantia
Thanks,

Just bumping this up!
the Haynes Manual said the Scuttle Panel is on the near side corner and the alarm is a key that you turn but I am not sure what I am looking for with regards to the scuttle panel what does one look like?

Please help a damsel in distress not to mention my neighbours ears cos the alarm keeps going off!

I always thought the scuttle panel was between the bonnet and the bottom of the windscreen (or the area behind the dashboard, from the inside)