S3 Alarm

[woody]

The alarm on my S3''s got an intermitent fault, it sets and un-sets but won''t go off unless I fiddle with the wiring. And then works about 3 or 4 times and then conks out again. Any way, my question is this, the alarm fitted is a Pirahna alarm, were these fitted as standard, and if so can the replacment box be bought (preferably in the Birmingham area) as I don''t want to mess about with the wiring to much. Cheers