It's started! went with 4x2" at 400mm centres. With the cost difference being a few quid overall it just made sense to do the best I could. I've got the Isover stuff bookmarked so will get a load in once we've got to that stage. Rewire first!
Proper acoustic rock wool + decent solid core door well fitted will prevent noise transfer to a large extent. You may find it flanks through the loft / floor though.
