I bought some insulation quilts in windsor sale for i think a pounf each. my bees survived fine without in recent years but sophistication is marching forward.
Sorry ... they are not the best insulation available, they are very thin and I can't think they will help much - Kingspan/celotex is much better and for about a quid more you would have got a sheet of 50mm in Wickes that would do two hives .. I keep my insulation on all the year round as any help you can give the bees in terms of maintaining the temperature THEY want in the hive has to be good.
I have some polystyrene of similar thickness, I get it free as a waste product. I might as well use a few layers of it in the roof or would I still be wasting my time?