Keeping your home warm / heating / energy crisis / insulation etc

I did ours using:

• Expanding foam tape externally between window frame and aperture (black stuff on a roll, not spray foam)
  
• Full fill of cavity/gap with Illbruck FM330 airtightness spray foam
  
• Tescon Vana airtightness tape to seal internal edges of window frames to internal reveals
  
• 20mm PIR pieces cut to fit snugly around all 4 sides of reveal, also taped along both edges
  
• Solido airtightness tape to finish the final edges and corners of window frame to PIR pieces. The corners need a special tape cutting detail to prevent pinholes forming
  
  

Seems a bit overkill now that I’m typing it out, but didn’t take too long and might as well do it correctly.