Please be gentle

[sKilled]

I know you guys are probably sick of alarm questions, but this is different. I have a different model to the one depicted on this forum. It's this one

the UK model. When I disconnected the battery to do some work on the boot cable tree (sheared through) upon reconnection the indicators flashed as did the LED on the dash, yet after starting the first time it did not restart blinking. My questions are as follows:

1. How do I go about checking to see if it is intact/operational?
2. How do I reactivate it?
3. Would any remote function as long as I could get the right chip?

Thanks in advance!