16 Sept 2012: [Extension] I had a number of visitors to the house on Sunday, looking at the technologies on the house, and the construction process of the house extension. When they heard that the third roof panel was not quite fitting, two of the visitors, Steve and Karl, offered to stay on and help fix it.
Karl's business is Ace Solar, doing PV and other renewables. He is strongly interested in using a ground source heat pump with a vertical borehole (or two) and is considering the best way to include solar earth charging. I don't think he is in any doubt that it is a good thing to do, but he might give it a try with a flat plate solar panel, the only one that I have not tried yet.
I'm terribly sorry to being so wrapped up with explaining everything to my guests that I forgot to take a picture of the visiting group. I also visited Tina Holt's house which is an eco-retrofit of a 1930s house, with insulation, MVHR and other design changes to bring it to Passivhaus level.