I am an architect and certified passivhaus designer working in the south West. I obtained planning permission (a minor miracle after huge amounts of work) last year to knock down my house in Wiltshire and replace it with an eco house. A passivhaus would be the aim but as the site is in AONB and Green Belt on a steep west facing slope with amazing views it has a few fundamental issues that will make this challenging, but seeing how close we can get will be the aim. I am trying to find time now outside office hours to work up the details and put it in PHPP and I will endeavour to post my progress for anyone who is interested.
The first issues will be how to deal with too much glazing facing the fantastic views, what to build it out of to keep walls as thin as possible (building volume is critical in Green Belt) with a partner who wants it "solid" and my own frivolous desire to have concrete floors throughout! Oh and stopping it falling down the slippery slope....