Above the auto-added rules, add a rule for interface WAN, source IP of your alarm, destination any, check static port. Save, apply changes.
Thanks cmb. I've tried it but I must have a mistake - still get the email from the alarm company that they only see me intermittently. If my IP of my alarm box is 192.168.1.9 then in the source it should be written 192.168.1.9/32 is that correct?