Sorry I haven't been getting notifications so I'll answer each point;
Sixwheeledbeast: No, it can't be. Maybe I've not been clear there are 4 PIRs and one door sensor. Each one has a 6 core going into it, they are not daisy chained. Into the control box is a 6 core from the bell box. And a second 6 core which brings in the 'switch' signal from each sensor on a single core, however I can only assume the other side of the switch is tied to ground or 12v in a mythical junction box who's location eludes me!
JMS: yes they must be jointed together but I have no idea where the junction is. I will have to double check the model number. I did try a search for a manual but couldn't find one, it's a generic wickes P.O.S
SJS it isn't a hash job, fitted as intended. See circuit board in first post. Panel was never moved my mum had the alarm fitted when there wasn't one before. So it is first installation.