97 Polo alarm deadlock

[pololady]

I recently got a Scorpion alarm fitted on my Polo.
When I had it fitted it came with a deadlock feature where as soon as I touched the brake the doors would lock and I wouldn't be able to unlock them unless I turned the engine off. I had a button fitted by the people that fitted my alarm so that I could press it and it would unlock the doors so that I could let people in and out of the car without having to turn the engine off.
A few weeks later I noticed that this deadlock feature no longer worked and I could open the doors with the engine still on without pressing the button, so I now have a button for no reason as the deadlock doesn't work.
The place I got it done from have said that this happens with Polos and that you can open the passenger door and the drivers door seperately but that if you unlock one door that it won't automatically open the other one.
I'm confused as i'm absolutely 100% certain that the reason that I got this button fitted was because I couldn't open the doors at all when I had the engine on and they are saying that its normal.
Also it should deadlock when the alarm is on, though if I sit inside the car and lock it then I can open the passenger door with the alram on but not the drivers door whereas i'm certain neither of them should be able to be opened with the alarm on.
Has anyone had anything similiar happen to them with a Scorpion or any other alarm? Should it deadlock as I think it should be doing? I just can't understand why they would say it's supposed to do that when I got the button put in because you couldn't open the doors.
Also when I lock the car, you can hear the doors lock and then after about 10-15 seconds you can hear the boot lock. Is it normal to have this delay also? It has been there since I got the car when it had an unnamed alarm on it.
Anyhelp would be appreciated as I really want to get ths sorted. Cheers