Welcome.
Now if that site is Subaruforester.org, then you should have been posting in the Europe forum where we are usually very keen to help.
The link Kim posted is over 34 pages long, so am surprised you replied in just 42 mins
Which model/year of forester do you have? No need just found you MY05 and living in Ireland.
Do you know the PIN code for the alarm keypad in coin tray by the drivers right knee??
The "chirping" could be a couple of things............(info found in that linked thread)
Low car battery condition.
Low alarm backup battery.
or you may have (by some means) turned on the warning "beeps" which are normally turned off.
These may be of assistance..........