Surveillance cameras
One can order video surveillance cameras or entire systems from several mail-order Chinese companies at a much lower price. Some even have depots in the UK, but interestingly, ordering from them the price is higher than ordering from China, only the delivery is much faster. There is an other type of camera without the net connectivity but it has 90 days standby time and one can really hide it very well. Unfortunately, I have never been able to find an other supplier apart from this German source:
http://www.pearl.de/a-PX8214-1322.shtml Sorry, it is in German but Google does a reasonable translation.