Hi Samuel23,
It's true you do have to have a sign outside telling of surveillance. You could register it with the local council too...
Now then, have a trawl through these...
http://www.crimereduction.gov.uk/cctv/cctv13.h tm
http://www.cctv-data-protection.info/legal1/
If it needs registering, and I don't think it does as it's not a business premises, then register it.
Our police are fantastic, but that's because we spoke to the Chief of Police via email......
It sounds like they're protecting the criminals and that's not good. Throw the book at them :-)