Hi all,   Please bear with me, it's going to sound stupid, but needs must.   Current house is a 1930's standard brick build, 100mm cavity, no insulation.  We're knocking it down in a couple of years and building new, but right now it's absolutely freezing. I work from home and run up £10 in gas yesterday and was still sat here at 18 degrees.  Loft has been insulated properly at least, and we're double glazed.  I've gone round with foam to make it airtight as possible, silicon around th