Thanks everyone!, Colin , a hot air gun is ideal for softening the plastic, get some old bottles cut up and have a bash! I recommend deep heat bubble bath bottles or wilkinsons economy
screenwash !! Its quite difficult to get it just right, -use stuff thats too thin or push the canopy former too far and it can end up very thin and floppy, not far enough and you dont get the full canopy shape , the advantage is that clear bits of plastic like this are everywhere so it doesnt cost anything to experiment. cheers tony