Over the last year of the Solar PV Feed in Tariff boom, an outcrop of installers set up to install a 'free' solar PV system onto your home or business have appeared.
These guys have been set up by investment companies specifically to harvest Feed in Tariff payments generated by homeowners systems, leaving the occupiers with minimal financial gain of free to use electricity during daylight hours.
Despite claims by some of these companies, the most anyone could realistically hope to get back as free to use electricity is around £150 a year, while the investing company will rake in £1500 a year FiT payments.
It makes sense to pay for your own system to be installed, avoiding issues such as ownership, and legal wrangles when you come to sell your house, etc
See http://www.which.co.uk/news/2010/09/free-solar-panels-not-such-a-great-deal-231808/ which highlights just how bad this deal is for the homeowner.