For those who missed out on the Argos deal, don't panic, just buy it cheaper!!
I just picked up this alarm system from Homebase for £93.19. It is on sale for £167.19, but they do a price match policy and are happy (strangely) to match the argos price, as they are the same company!
Plus, they will refund 10% of the difference!
Just take a printout of the argos deal into the store and fill ya boots!