Update on this. So far I have received replies from three of the companies I contacted. Here’s the summary:
WeberHaus – they are expensive. It’s gonna be over £360k all in for a 200sqm house (£1,800+ per m2), which is the smallest they do. And that does not include ground works.
Huf Haus – they are really expensive. Gonna be over £450k for a 170sqm house (approx £2,600 per sq meter), which is the smallest they will do.
These prices are pretty crazy, but I think it’s worth pointing out that these two companies are at the top end of the market in terms of design and quality, and the size of house I am looking at is tiny for them – I think they are better value if you are building something a lot bigger.
Svenskhomes – this is more what I had in mind. Approx £260k for a 160sq meter house (£1,500 per sq meter). This is for an off-the-shelf design such as this or this. They will also work with architects to build whatever you want, which will of course alter the price depending on what you want.
No replies form the other 5 or 6 suppliers yet…