You got the engineer in to change the battery. One takes it you did not instruct him o make the alarm sound at night. Get him back in to put right his cockup and to do so on his nickel.
Alternatively find a manual and use that.
http://www.touchpoint-online.com/sites/default/files/9448_plus_endstation_inst_496284_iss5_uk.pdf
http://barumfriendsecurityltd.co.uk/PDF/User%20Manuals/Intruder%20Alarm%20Panels/9448%20plus%20user%20guide.pdf
http://www.templewood.co.uk/documents/9448Discontinued.pdf
Anon
July 2016