I have just joined the forum - we are building in Northumberland. House still in planning. This thread is quite old now. What did you (DNB) do in the end? Does it work? I am really intere3sted to find out. HVAC does seem to be an alien concept round here and even more so when i suggest combining it with MVHR while heating.
I am pretty certain that overheating is a serious issue for us so am very interested in this. We had experience of HVAC when living in Canada (annual temperature range -40 to +35) about 15 years ago.
Any update would be greatly appreciated.