In reply to Alan M:
I looked into this when I was having neighbour problems. The easy part was getting cameras, which I got from Maplins. The hard part was finding suitable software. I tried just about every available free and free to try security software before signing with Sighthound.
https://www.sighthound.com
I have one camera, with excellent night time vision, plugged into a USB dongle working off its own dedicated second hand computer which I bought from this very site.
I have the computer working 24/7 which reboots itself once a week. I discovered that the computer kept falling if left on endlessly. I do not have a monitor, mouse, or keyboard attached to the computer. I chose to install Teamviewer which allowed me to work/view the computer from anywhere in the world saving the need to buy a monitor.
I kept my project on a budget.
I did buy a dedicated camera+PVR kit from Maplins but the kit had one major flaw in that it recorded in a propriety format which could only be viewed on the PVR device. Not exactly a good idea if you can't get the evidence off to give to the police.
Post edited at 22:59