If there’s crawl space under your floor you don’t need to pull it all up but it’ll be a grim job that might involve a bit of tunnelling through walls/piers supporting the floors at mid span. Helpfully someone has already done this in mine, unhelpfully it’s below the local water table making for a difficult work environment!
Keep attacking the draughts, you can hunt them with smoke or a candle, ideally in different wind directions. Check electrical fittings/outlets for draughts.
Some ceiling lights will tolerate a metal hat then insulation over them or you can get fire rated sealed LED units that work under insulation, depends what you have and how attached to them…[Read more]
@fuzzy I think less obsessive use of bleach, detol, anti bacterial everything & anything around our homes will have more impact in increasing our tolerance of everything that is around us. We are more bacterial than human, but through media have become obsessed at killing them, the good ones and the baddies.