As a matter of interest, how do prices compare to here? I built mine in 2005 - 4 double bedrooms, 2 with ensuite; large lounge, diningroom, family room/kitchen, and large family bathroom, landscaping a mixture of gravel, lawn, fruit beds, shrubs. My land was already owned by us (at the bottom of the garden and we owned the tracks all round it so no-one else could build on it so we got it cheap) The total cost including the land was around £150,000. It was worth double that the minute I got turnkey.
I'm interested in renewables too, been thinking of investing in solar production, just waiting for another two companies to quote.