No.. what you are saying makes sense ... but, if you have drawn frames then a couple of frames that they can fill with stores will give them a better chance of getting through most of winter without running out. The brood nest will reduce but if it's already a big colony the stores situation is going to be important.
So .. I'd still go for the option of putting them into a hive and dummy down the space they are not using, give them a couple of frames to fill - I know winter comes on very quickly up there so you will find that as it gets colder they will be less likely to cap the stores but if you feed them Invert syrup it won't matter too much if it doesn't get capped. Warmth in the hive is important for them to cap stores so a poly hive and dummied down is ideal.
However, Bubble wrap is not the ideal insulator - it's better than nothing - you should really try and find some PIR (Celotex/Kingspan/Recticel) as it has a huge insulation value. You can cut slabs to fill the void completely and seal the cut edges with aluminium tape and just put the slabs straight into the hive. The bees won't eat into the aluminium tape or the foil surfaces of the PIR.
Do you have Toolstation anywhere near you ? This is the aluminium tape I use ..
https://www.toolstation.com/aluminium-foil-tape/p81953
and Wickes sell this:
https://www.wickes.co.uk/Kingspan-TW50-Insulation-Board---1200-x-450-x-50mm/p/180440