306 xsi Rear knocking and no alarm

Hi guys, Im from the UK and have recently brought a 1996 306 XSI 2.0 after my crappy rover 214 engine cracked (P.S dont buy Rovers!) and I love it but I have a couple of issues with it and out of all the forums you guysseem the ones to ask for help, so here goes:-

1. There is a knocking sound that comes from the rear left hand side of the car whenever I go over holes or and small but abrupt changes in the road and also if I brake fairly hard (by the way it has disc brakes all round). It seems to be fine at all other times and when going over smooth bumps and still corners and handles fine.

2. Some idiot broke into the car the other day and set off the pressure sensors when I got back the light was flashing to say the alarm had been activated in my absance, but it never sounded. I have done tests since and found all aspects of alarm to function correctly however the horn or lights never activate. I can here a clicking coming from the relay box near the battery as if it trying to sound but nothing actually happens and after about 15 seconds this stops also aslong as the alarm is not tiggered again. The car has a (assumed) factory fit alarm and full central locking activated by a double button pug key/remote, and a keypad operated imobiliser.

3. Is there any way to make the above alarm system full closure (eg. close electric sunroof and windows?

Many thanks in advance and I hope you guys can help me out.
Cheers
Sean

one common problem with the early 306's as far as noise from the rear could be the radius arm bearings the check for this is to raise the vehicle and grasp the wheel and see if any movement is present when you try to move it side to side or up and down with someone checking the radius arm pivot point if movement is evident then the bearing has failed, if this happens and the failure is bad the wear is transfered to the axle tube itself this unfoutunately means cmplete rear suspension replacement (this is worse case not necessarily your case!) as fasr as the clicking noise that is your alarm ecu trying to work the siren (under the nsf wing) but the siren is possibly faulty on some 306's there is an alarm siren override switch on the slam panel next to the nsf head light its a key switch and they mostly didnt work anyway hope this helps :-)