From various reliable sources, I found the following details for

Control Centre	0870 600 6008	Reset Alarm or Update details
Service Bureau	0870 600 6005	Report Faults or Request Inspections
Telemarketing	0800 010 999	Sales/Upgrades, Change of Address/payments

Head Office	. . . .	Manchester Office
Security House	. . . .	Quay House
The Summit	. . . .	City Pk Business Village
Hanworth Road	. . . .	Brindley Road
Sunbury on Thames	. . . .	Manchester
Middx.  TW16 5DP	. . . .	M16 9UN
Tel: 01932 743333	. . . .	Tel: 0161 2525500
Fax: 01923 743155	. . . .

From enquiries made, the Control Centre is at the Manchester office. If you do some rooting around there in office hours might get you more, but the switchboard was closed.
Hope this helps you & if I find any more I will update this.