Please note that the Government is bringing about changes in the Solar PV Feed-in Tarrif (FIT) scheme. Eligible installations completed and signed off before the December 12, 2011 cut-off date will get the current high rate tariff.
According to The Energy Saving Trust the changes will result in the introduction of a reduced rate of 21p/kWh for solar PV installations less than 4kW in size, from 1 April 2011 to affect all installations with an eligibility date on or after 12 December 2011.
For more information please see this page on The Energy Saving Trust's website.

