We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember "george [dicegeorge]"
saying something like:

so you havent the hassle of dismantling it, wire and pipe routing and
lots of coldbridging,
you mean to glue kingspan to the outside
and then weatherseal that with another layer?

That's my plan, fwiw.
I was buggering around thinking up ways of doing it, then realised, as
this is actually an old agriculturally-related building, some insulated
box sheeting would look right in place. 100mm of Kingspan bonded to PVC
coated steel and only needs to be through-bolted every couple of feet.
Sorted.
By using seconds I can slash the cost dramatically.