3.3 kWp, 20% efficient Sunpower solar system with SMA inverter on two strings, owing to partial shading late in the day (especially winter). A great system, its annual generated electricity pretty much matches our total consumption. Obviously we net export during the day and import at night, but LED lights have minimised that.
Teacher of Physics and Sustainability in a wonderful Cambridge school. Keen cyclist (yes, a 15 mile round commute 6 days a week!) and photographer. Former panel member of the now defunct Sustainable Development Commission. Owner/author for GCSE.com website.
Before insulating in the loft to "modern standards" do check that the ceiling underneath is as air tight as it can be. We had 3-5 mm gaps around beams that meant hot, moist air in the winter was entering the loft space. This condensed on the sloping roof and - literally - rained on the insulation! Sealing the gaps stopped the condensation.