Apologies if this is teach granny stuff but I thought this was worth sharing for anyone renovating/working on a trad Scottish house (like mine). Historic Scotland have been running a number of trials in trad buildings with insulation upgrades and there's some really good info I've found on their website and videos.  The video below is about a trial done in Holyrood house and the interesting part is about the insulation trial in the roof. This was WF insulation installed with the standard 50